### Clue: Big cheese Diana Ross once cut to get slice of Ossau-Iraty (7)
### Answer: SUPREMO 
 ### Explanation: Definition: Big cheese
 "Supremes"(the singing group once headed by Diana Ross) **minus last letter of**(cut) **plus**(to get) **1st letter of**(slice of) "Ossau-Iraty".
The big and the small cheeses: