Microwave Fudge
["1/2 c. butter or margarine", "2 c. sugar", "1 (5 1/3 oz.) can (2/3 c.) evaporated milk", "2 c. tiny marshmallows", "1 (6 oz.) pkg. (1 c.) semi-sweet chocolate pieces", "1/2 c. chopped walnuts", "1/2 tsp. vanilla"]
["Line an 8 x 8 x 2-inch baking pan with foil, extending foil over edges of pan.", "Butter the foil; set pan aside."]
["butter", "sugar", "milk", "marshmallows", "semi-sweet chocolate pieces", "walnuts", "vanilla"]