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                                                                    Exhibit 10.7
                       FIRST AMENDMENT TO OFFICE SUBLEASE
                       ----------------------------------

          THIS FIRST AMENDMENT TO OFFICE SUBLEASE (this "AMENDMENT") is
effective as of this 1st day of May, 1998, by and between Boston Chicken, Inc.,
a Delaware corporation ("LANDLORD"), and Einstein/Noah Bagel Corp., a Delaware
corporation ("TENANT").

                                   RECITALS:

          R-1.  Prudential Insurance Company of America and its successors and
assigns ("PRUDENTIAL"), as landlord, and Landlord, as tenant, are parties to a
Lease Agreement dated December 20, 1996 (the "MASTER LEASE"), wherein Prudential
leased to Landlord and Landlord leased from Prudential, one office building
containing approximately 62,746 square feet, having a street address of 14103
Denver West Parkway, Golden, Colorado 80401 ("BUILDING NO. 1") and one office
Building containing approximately 94,918 square feet, having a street address of
14123 Denver West Parkway, Golden, Colorado 80401 ("BUILDING NO. 2").

          R-2. Landlord and Tenant entered into an Office Sublease dated as of
December 20, 1996 (the "SUBLEASE"), wherein Landlord subleased to Tenant and
Tenant subleased from Landlord approximately 32,585 square feet located on the
second floor of Building No. 2 and approximately 5,375 square feet located in
the basement of Building No. 2, known as the test bakery (the "TEST BAKERY"),
for a total of 37,960 square feet (together, the "ORIGINAL PREMISES").

          R-3.  The term of the Sublease expires on December 30, 2001.

          R-4.  Tenant desires to (i) retain only that portion of the Original
Premises known as the Test Bakery, and (ii) relocate the office portion of
Tenant's business from the Original Premises to new premises located on the
first floor of Building No. 1, containing approximately 21,625 square feet (the
"NEW OFFICE PREMISES"), and to amend certain other terms of the Sublease as
provided in this Amendment.   The Test Bakery and the New Office Premises are
collectively referred to hereafter as the "NEW PREMISES," which contains a total
of approximately 27,000 square feet.  The legal description of Building No. 1 is
attached hereto as EXHIBIT A, and the floor plan of the New Office Premises is
attached hereto as EXHIBIT B.

                                   AGREEMENT

          NOW, THEREFORE, in consideration of the agreements herein contained,
the parties hereto agree as follows:

          1. Incorporation of Recitals.  The foregoing recitals are incorporated
             -------------------------                                          
herein and made a part hereof to the same extent as if set forth herein in full.
<PAGE>
 
          2. Lease of New Premises.  Effective as of May 1, 1998 (the "EFFECTIVE
             ---------------------                                              
DATE"), Landlord leases to Tenant, and Tenant leases from Landlord the New
Office Premises, upon the same terms and conditions as are stated in the
Sublease, except as modified by this Amendment. Landlord shall continue to lease
to Tenant, and Tenant shall continue to lease from Landlord the Test Bakery,
upon the same terms and conditions as are stated in the Sublease, except as
modified by this Amendment. From and after the Effective Date, the term
"Building" as used in the Sublease shall mean Building No. 1, (except that any
references to "Building", as it relates to the Test Bakery only shall mean
Building No. 2) and the term "Premises" as used in the Sublease shall mean the
New Premises.

          3. Surrender of Original Premises.  On or before the Effective Date,
             ------------------------------                                   
Tenant shall surrender the Original Premises (except for the Test Bakery) to
Landlord broom clean and in good condition, normal wear and tear excepted.

          4. Rent.  Notwithstanding anything to the contrary in Section 
             ----   
1(a)(vi) of the Sublease, commencing on May 1, 1998, and continuing on the first
day of each month thereafter until December 30, 2001, Tenant shall pay Landlord,
as Rent due under the Sublease for the New Premises, the sum of $27,000.00 per
month.

          5. Rent for Extension.  Section 1(a)(xi) of the Sublease is hereby
             ------------------                                             
deleted in its entirety and the following is substituted in its place:
 
             (xi)      Rent for Extension(s):
 
             Lease Years    Annual Rent   Monthly Rent
             -------------  -----------   ----------------------
 
             6-10           $372,606.00               $31,050.53
             11-15          $428,497.00               $35,708.06
             16-20          $492,759.00               $41,063.22
             21-25          $567,009.00               $47,250.77
             26-30          $651,791.00               $54,315.91

          6. Common Areas/Taxes and Insurance/Building Operating Costs.  
             ---------------------------------------------------------
Section 8 of the Sublease is hereby deleted in its entirety and the following is
substituted in its place:

          8.1.  Common Areas.   During the Term hereof, Tenant shall have a non-
                -------------                                                  
               exclusive easement to use the common areas in the Building
               including the entrances and exits, public hallways, reception
               area, stairways, elevator, eating areas, public rest rooms and
               work out facilities, excluding, however, areas intended for the

                                      -2-
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               exclusive use of the Landlord and other tenants or occupants in
               the Building, all as outlined on EXHIBIT C, attached hereto and
               incorporated herein by this reference (the "Interior Common
               Areas"). During the Term hereof, Tenant shall have a non-
               exclusive easement to use the common areas of the Property
               including the curb cuts, driveways, parking areas, walkways,
               service drives and loading docks on the Property, all as outlined
               on EXHIBIT D, attached hereto and incorporated herein by this
               reference ( the "Exterior Common Areas"). The Interior Common
               Areas and the Exterior Common Areas may hereafter be collectively
               referred to as the "Common Areas". Common Areas shall include
               those areas and facilities designated from time-to-time by
               Landlord , and the use of the Common Areas by Tenant shall be
               subject to the use thereof by Landlord, and Landlord's tenants
               and its and their officers, directors, employees, shareholders,
               customers, invitees, agents and contractors, the exclusive
               control and management of Landlord, and the rules and regulations
               promulgated from time to time by Landlord in its discretion.

               Landlord shall operate, repair, replace and maintain the Common
               Areas in a first class manner.  Landlord reserves the right to
               make changes to the Common Areas, construct and install temporary
               or permanent improvements and make such use of the Common Areas
               from time to time in Landlord's sole discretion.  In the event
               that Landlord fails to so operate, repair, replace and maintain
               the Common Areas in a first-class manner, after receipt of
               written notice by Tenant and an opportunity to cure the same
               within a reasonable amount of time, not to exceed fourteen (14)
               days, Tenant shall have the right, but not the obligation, to
               perform or arrange for the performance of such operation, repair,
               replacement and maintenance of the Common Areas to maintain said
               Common Areas in a first-class manner.  Notwithstanding the
               foregoing, if Landlord has commenced to cure the default within
               the fourteen (14) day period set forth above, such default is not
               capable of being cured within such time frame, and Landlord is
               diligently prosecuting the cure, then Landlord shall have an
               additional reasonable period of time to effect such cure.  If
               Tenant so elects to perform or arrange for the performance of
               such operation, repair, replacement and maintenance of the Common
               Areas, Tenant shall be entitled to an offset or abatement of Rent
               in an amount equal to the reasonable cost of such services.

 
          8.2.  Taxes and Insurance.
                --------------------

                8.2.1. Definitions.  The following terms shall have the
                       following meanings with respect to the provisions of this
                       Sublease:

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                    (a)  "Base Year" shall mean calendar year 1998.
                          ---------                                

                    (b)  "Taxes" shall mean any form of assessment, tax, levy,
                          ----- 
                         or charge imposed by any authority having the direct
                         power to tax, including any city, county, state or
                         federal government or other improvement or special
                         district, against the Premises, Building, Common Areas,
                         or Property, or any legal or equitable interest of
                         Landlord therein.

                    (c)  "Insurance Costs" shall mean Landlord's cost to
                          ---------------                                
                         provide insurance for the Property, Building, Common
                         Areas and all other improvements to the same.

                    (d)  "Tenant's Prorata Share" shall mean a fraction, the
                          ----------------------                            
                         numerator of which shall be 27,000 (the number of
                         square feet in the Premises), and the denominator of
                         which shall be 62,079 ( the number of square feet in
                         the Building).  Tenant's Prorata Share as of the
                         Effective Date is 43.49%.  At such time, if ever, any
                         space is added to or subtracted from the Premises or
                         the Interior Common Areas, Tenant's Prorata Share shall
                         be adjusted by Landlord accordingly.

                    (e)  "Tenant's Prorata Share of Taxes and Insurance Costs"
                          --------------------------------------------------- 
                         shall mean Taxes and Insurance Costs multiplied by
                         Tenant's Prorata Share.

                    (f)  "Base Year Taxes" shall mean the Taxes for the Base
                          ---------------                                   
                         Year.

                    (g)  "Base Year Insurance Costs" shall mean the Insurance
                          -------------------------                          
                         Costs for the Base Year.

                    (h)  "Tenant's Prorata Share of Base Year Taxes and Base
                          --------------------------------------------------
                         Year Insurance Costs" shall mean Base Year Taxes and
                         --------------------                                
                         Base Year Insurance Costs multiplied by Tenant's
                         Prorata Share.

            8.2.2.  It is hereby agreed that commencing with calendar year
                    1999 and each calendar year thereafter until the Expiration
                    Date, Tenant shall pay Tenant's Prorata Share of Taxes and
                    Insurance Costs in excess of Tenant's Prorata Share of Base
                    Year Taxes and Base Year Insurance Costs.  Such amount shall
                    be paid by Tenant in equal monthly installments, as
                    additional rent hereunder, at the times and in the manner 

                                      -4-
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                    of payment of Rent, in such amounts as are estimated by
                    Landlord from time to time during the Term.

            8.2.3.  Landlord shall provide a written reconciliation statement
                    with respect to Taxes and Insurance Costs  to Tenant within
                    sixty (60) days of the end of each calendar year, and any
                    amount owed to Landlord shall be paid by Tenant within
                    twenty (20) days after receipt by Tenant of such written
                    reconciliation statement from Landlord.  Any amount owed to
                    Tenant by Landlord shall be credited toward the next
                    estimated payment(s) of Taxes and Insurance Costs.
                    Notwithstanding  the foregoing however, if Tenant's Prorata
                    Share of Taxes and Insurance Costs  for any calendar year is
                    less than the Tenant's Prorata Share of Base Year Taxes and
                    Base Year Insurance Costs Tenant shall not be entitled to
                    any credit or refund for such difference.

            8.2.4.  Tenant's obligation with respect to its Prorata Share of
                    Taxes and Insurance Costs shall survive the expiration or
                    early termination of this Sublease.  If the last year of
                    the Term of this Sublease, as may be extended, ends on any
                    day other than the last day of December, any payments due to
                    Landlord of Tenant's Prorata Share of Taxes and Insurance
                    Costs, shall be prorated on the basis by which the number of
                    days in such partial year bears to 365.

            8.2.5. Upon request by Tenant, Landlord and Tenant shall set up an
                    escrow account, to be governed and controlled by mutually
                    acceptable commercially reasonable joint escrow
                    instructions, with a mutually satisfactory financial
                    institution or other third party, to be used by Tenant for
                    the payment of Tenant's Prorata Share of Taxes and Insurance
                    as contemplated herein.

          8.3.  Building Operating Costs.
                ------------------------ 

            8.3.1.  Definitions.  The following terms shall have the
                    -----------                                     
                    following meanings with respect to the provisions of this
                    Sublease:

                    (a)  "Building Operating Costs" shall  mean all costs
                          ------------------------                       
                         involved in the ownership, operation, upkeep,
                         maintenance, repair and replacement of the Building,
                         Premises and Common Areas during the Term and any
                         extensions, including without limitation, the
                         following: any costs, expenses or fees borne or 

                                      -5-
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                         paid by Landlord under the terms of the Master Lease;
                         utility charges including electrical, gas, water,
                         sewer, lighting, heating, air-conditioning, and
                         ventilating services; license, permit and inspection
                         fees; cost of services of independent contractors,
                         property management fees, and cost of compensation
                         (including employment taxes and fringe benefits) of all
                         persons who perform regular and recurring duties
                         connected with the day-to-day operation, maintenance,
                         management and repair of the Building, Premises and
                         Common Areas; trash removal; landscaping and gardening;
                         elevator repairs and maintenance;  window washing;
                         reserves for replacement; rental expenses or a
                         reasonable allowance for depreciation of personal
                         property used in the maintenance, operation and repair
                         of the Building. Building Operating Costs shall not
                         include: (i) Taxes , (ii) Insurance Costs, (iii) the
                         cost of work performed exclusively for other tenants or
                         prospective tenants, (iv) the cost of work covered by
                         insurance proceeds or a condemnation award; (v) leasing
                         and brokerage commissions; and (vi) amortization of
                         principal and interest expense with respect to
                         Landlord's financing.

                    (b)  "Base Year Building Operating Costs" shall mean that
                          ----------------------------------                 
                         certain dollar amount to be calculated as follows:
                         Seven and 00/100 Dollars ($7.00) per square foot  minus
                         Base Year Taxes per square foot, minus Base Year
                         Insurance Costs per square foot.

                    (c)  "Tenant's Prorata Share of Base Year Building Operating
                          ------------------------------------------------------
                         Costs" shall mean Base Year Building Operating Costs
                         -----                                               
                         multiplied by 27,000 (the number of square feet in the
                         Premises)

            8.3.2.  It is hereby agreed that commencing with calendar year 1999,
                    Tenant shall pay in equal monthly installments, as
                    additional rent hereunder, at the times and in the manner of
                    the payment of Rent, the three percent (3%) increases over
                    the previous years Building Operating Costs as set forth
                    below. Commencing with calendar year 1999, however, Tenant's
                    Prorata Share of Base Year Building Operating Costs shall be
                    increased by three percent (3%) each calendar year until the
                    Expiration Date, and Tenant shall pay such increases over
                    the Base Year Building Operating Costs to Landlord as
                    additional rent. ( For purposes of illustration, if Tenant's
                    Prorata Share of Base Year Building Operating Costs equal
                    $5.00 per square foot, then Tenant's Prorata Share of
                    Building

                                      -6-
<PAGE>
 
                    Operating Costs in calendar year 1999, would equal $0.15 per
                    square foot ($5.00 x 3%); Tenant's Prorata Share of Building
                    Operating costs in calendar year 2000 would equal $.30 per
                    square foot ($5.15 x 1.03 -$5.00); and Tenant's Prorata
                    Share of Building Operating costs in calendar year 2001
                    would equal $.46 per square foot ($5.30 x 1.03 -$5.00)
                    etc... ).

            8.3.3.  Tenant's  obligation as set forth in Section 8.3 hereof
                    shall survive the expiration or early termination of this
                    Sublease.  If the last year of the Term of this Sublease, as
                    may be extended, ends on any day other than the last day of
                    December, any payments due to Landlord in accordance with
                    Section 8.3 hereof, shall be prorated on the basis by which
                    the number of days in such partial year bears to 365.

       7. Access to Test Kitchen and Test Bakery. The parties hereto acknowledge
          --------------------------------------                                
and agree that Landlord, and its officers, directors, employees, shareholders,
customers, invitees, agents and contractors shall continue to have undisturbed
access to and from the Boston Market Test Kitchen identified on EXHIBIT B, and
Tenant, and its officers, directors, employees, shareholders, customers,
invitees, agents and contractors shall continue to have undisturbed access to
and from the Test Bakery identified on EXHIBIT B.

       8. Insurance.  Section 16 of the Sublease is hereby deleted in its
          ---------                                                      
entirety and the following is substituted in its place:

          16.1    Tenant's Insurance.
                  ------------------ 

          16.1.1. Coverage.  Tenant shall, at all times during the term of this
                  --------                                                     
                  Sublease, and at its own cost and expense procure and continue
                  in force the following insurance coverage:

                  (a)  Comprehensive commercial general liability insurance
                       (including Tenant's legal liability coverage) with a
                       combined single limit for bodily injury and property
                       damage of not less than $1,000,000 per occurrence, or
                       such higher amounts and coverages as Landlord may
                       reasonably require.

                  (b)  Property Damage, and Fire Insurance including vandalism,
                       malicious mischief, and all extended coverage
                       endorsements in an amount equal to the full replacement
                       value of all fixtures, furniture and improvements
                       installed and/or owned by Tenant.

                                      -7-
<PAGE>
 
       16.1.2. Insurance Policies.  The aforementioned minimum limits of
               ------------------                                       
               policies shall in no event limit the liability of Tenant
               hereunder. The aforesaid insurance shall name Landlord and
               Landlord's lender(s) and Master Landlord as additional insureds.
               Said insurance shall be with companies having a rating of not
               less than a Class A (vii) in "Best's Key Rating Guide". Tenant
               shall furnish from the insurance companies or cause the insurance
               companies to furnish certificates of coverage. No such policy
               shall be cancelable or subject to reduction of coverage or other
               modifications or cancellation except after thirty (30) days prior
               notice in writing to Landlord by the insurer. All such policies
               shall be written as primary policies, not contributing with and
               not in excess of the coverage which Landlord may carry. Tenant
               shall, at least twenty (20) days prior to the expiration of such
               policies, furnish Landlord with renewals or binders. Tenant
               agrees that if Tenant does not take out and maintain such
               insurance, Landlord may (but shall not be required to) procure
               said insurance on Tenant's behalf (excluding insurance on
               Tenant's personal property) and charge Tenant the premium
               together with a twenty-five percent (25%) handling charge,
               payable upon demand. Tenant shall have the right to provide such
               insurance coverage pursuant to blanket policies obtained by
               Tenant provided such blanket policies expressly afford coverage
               to the Premises and to Tenant as required by this Sublease.

        16.2.  Landlord's Insurance. Landlord shall maintain "All Risk"
               --------------------                                    
               property insurance on the Property, Common Areas, Building and
               all other improvements on the Property for the full replacement
               cost thereof.  Landlord shall maintain comprehensive general
               public liability insurance against claims for bodily injury or
               property damage occurring in or about the Property, Building and
               Common Areas in the following minimum amounts:

               $1,000,000.00 with respect to the injury to or death of a single
               person.
               $2,000,000.00 with respect to the injury or death of more than
               one person.
               $250,000.00 with respect to property damage.

               or such additional coverages and such increased amounts of
               coverage as Landlord in its reasonable judgment shall determine
               from time-to-time.  At Tenant's request Landlord shall provide
               Tenant with a Certificate of Insurance naming Tenant as an
               additional insured with respect to the general liability coverage
               as to the Common Areas.

        16.3.  Waiver of Subrogation.  Landlord and Tenant each hereby waive
               ---------------------                                        
               any and all rights of recovery against the other or against the
               officers, directors, shareholders, employees, agents, contractors
               and representatives of the other to 

                                      -8-
<PAGE>
 
               the extent that such loss or damage is insured against in any
               insurance policy which either party may have in force at the time
               of such loss or damage. Tenant shall, upon obtaining the policies
               of insurance required under this Sublease, give notice to the
               insurance carrier or carriers that the foregoing mutual waiver of
               subrogation is contained in this Sublease. Landlord and Tenant
               shall, from time to time, upon request, cause their respective
               insurers to issue appropriate waiver of subrogation rights
               endorsements to all property insurance policies carried in
               connection with the Building or the Premises or the contents of
               either.

       9. 1998 expenses for Building Operating Expenses, Taxes and Insurance.
          ------------------------------------------------------------------  
Notwithstanding anything contained in the Sublease to the contrary, as of the
Effective Date, and through the end of calendar year 1998, Tenant shall pay to
Landlord Seven and 00/100 Dollars ($7.00) per square foot (on an annual basis)
for its share of Building Operating Expenses, Taxes and Insurance, prorated
based upon eight months of occupancy (May - December, 1998).  For purposes of
illustration, Tenant shall pay an amount equal to $126,000.00 ($7.00 x 27,000
sq.ft. x 8/12 = $126,000) payable on a monthly basis in the amount of
$15,750.00 commencing on the Effective Date and monthly thereafter on the first
day of each month through the end of calendar year 1998.

      10. Tenant's Notice Address.  As of the Effective Date, Tenant's notice
          -----------------------                                            
address for all purposes under the Sublease shall be Einstein/Noah Bagel Corp.,
14103 Denver West Parkway, Golden, Colorado 80401, Attn:  Legal Department.
 
      11. Non-Disturbance Agreement.  Landlord shall use its best efforts to
          -------------------------                                         
obtain a non-disturbance agreement from Prudential, in a form reasonably
satisfactory to Tenant, wherein Prudential agrees that, if Landlord is in
default under the Master Lease, Prudential shall not disturb Tenant's rights
under the Sublease, so long as Tenant is not in default thereunder.
 
      12. Ratification of Sublease.  All terms and conditions of the Sublease
          ------------------------                                           
are hereby ratified and affirmed, as modified by this Amendment.

      13. Capitalized Terms.  All capitalized terms in this Amendment shall have
          -----------------                                                     
the same meanings as in the Sublease unless expressly provided otherwise herein.

                                      -9-
<PAGE>
 
     IN WITNESS WHEREOF, the parties have caused this Amendment to be executed
under seal as of the date first above written.

                              LANDLORD:

                              BOSTON CHICKEN, INC.,
                              a Delaware corporation

                              By:  /s/ Michael R. Daigle
                                 -----------------------------
                              Name:    Michael R. Daigle
                                   ---------------------------
                              Title: Senior Vice President and General Counsel
                                    -------------------------------------------


                              TENANT:

                              EINSTEIN/NOAH BAGEL CORP.,
                              a Delaware corporation

                              By:  /s/ H. Andrew Fox
                                 -----------------------------
                              Name:    H. Andrew Fox
                                   ---------------------------
                              Title: Vice President Real Estate and Development
                                    -------------------------------------------


 

                                      -10-
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Exhibits:
-------- 

Exhibit A - Legal Description of Building No. 2
Exhibit B - Floor Plan of the New Office Premises
Exhibit C - Interior Common Areas (Floor Plan)
Exhibit D - Exterior Common Areas (Floor Plan)

                                      -11-
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                                   EXHIBIT A
                                   ---------

Lot 1 of Denver West Properties Amendment No.4, recorded December 19,1996 at
Reception No. F0347080, Plat Book 133 at Page 12, located in the Southwest 1/4
of Section 31, Township 3 South, Range 69 West, County of Jefferson, State of
Colorado, a reconfiguration of the common lot lines in Office Park Activity
Areas 4,5,7 and 8 of Denver West Properties, a subdivision recorded December 14,
1989 in Book 102, at Page 23, Reception No. 89108643.

County of Jefferson
State of Colorado