Line a 13" x 9" pan with aluminum foil, butter the insides, and set aside. Place chips, vanilla & butter flavor, about half the marshmallow creme, chilled butter, and nuts into a LARGE saucepan or Pyrex glass dish and set aside (or in the refrigerator). Use Medium heat to bring the milk and sugar to a rolling boil while stirring constantly with a wooden spoon or single stem hand mixer. Add marshmallow creme - fold in - the boil will stop. Bring back to a rolling boil and continue to boil for 8 full minutes by the clock (start timing once all the marshmallow has completely dissolved and the boil has resumed). Use the lowest flame possible to keep the rolling boil. The mixture will expand and start to turn brown during the boil. If you get brown flakes in the mixture then turn down the heat a little and continue stirring. Remove from heat and pour hot mixture over chips, vanilla, butter, butter flavor, and nuts without scraping the sides of the hot saucepan. Mix thoroughly and pour into prepared pan. Cool 2-3 hours at room temperature. Remove from pan, remove foil, cut into squares. Store in an airtight container with wax paper dividers for up to 2 weeks. Makes about 4 pounds of fudge. NOTES: * THE STUFF GROWS: After adding the Marshmallow Creme and butter to the hot milk/sugar solution, the volume will expand to almost twice the original volume. So use a sufficiently large sauce pan (4 quart or better). As the boil continues, the volume will begin to contract. Stirring is important to help distribute the heat throughout the mixture and prevent scorching. Remember, this recipe calls for two [2] sauce pans -- one to boil and one to mix. * YOU CAN SUBSTITUTE: If you don't have access to milk chocolate chips then you may use 24 ounces of semisweet chocolate chips - though it has a stronger chocolate taste. Two large Hershey bars (7 ounces each) will more than substitute for the milk chocolate chips. You can also use 24 ounces of white Chips for an excellent Vanilla Fudge. Don't be shy about substituting mini-marshmallows for the Marshmallow Creme. * MAKE HALF A BATCH: You may cut the recipe in half (using exactly 1/2 the amount of everything) but the boil time must be reduced to [5] full minutes by the clock. I would also recommend a 9" x 9" pan. You can also substitute 5 ounces of evaporated milk (one small can) for 6 ounce (half a large can). * PERSEVERE: This is a much more liquid mix (more 'soupy') than other fudge recipes and you might get discouraged midway. Keep going. I've nearly given up several times only to have it set extremely well once cast. * NERVOUS NELLY: If you're afraid this won't set (and it will) or if you just want a more firm fudge then bring the milk and sugar to a rolling boil for a full minute before adding the marshmallow. During the second boil (after the marshmallows are dissolved) go for 9 or 10 minutes. This will set very quickly and be a much firmer fudge. * DON'T PANIC: If you use a candy thermometer (and this recipes *does not call for a candy thermometer*) the temperature will not reach the normal 232-236°F found in other fudge recipes. It will attain something around 220-224°F Don't panic! This is a whole different way of making fudge. The mixture will set once cast. * STORAGE: Fudge will keep for up to two weeks at room temperature. You'll need to store it wrapped in waxed paper (cut it up into reasonable segments) and in an airtight container. Fudge will keep frozen for up to six months. When freezing fudge you'll need to wrap in waxed paper, store in a double-airtight container. I use double freezer Baggies. Thaw fudge at room temperature in its air-tight container -- it will take most of one day. * SOFTNESS: This produces a medium-hard fudge. If you prefer a softer fudge (or if the weather is especially dry on the day you make the fudge -- like snowing or you live in the desert) then boil for only [7] minutes instead of the recommended [8] minutes. Conversely, if you'd like a firmer fudge (or if the weather is especially damp on the day you make fudge) then boil for [9] minutes instead of the recommended [8] minutes.