Microwave Rocky Road Fudge

1 (12 oz.) pkg. semi-sweet chocolate chips
1 (12 oz.) pkg. butterscotch chips
1/2 c. butter
1 (10 1/2 oz.) pkg. miniature marshmallows
1 c. peanuts

In 4-quart microproof mixing bowl combine chocolate, butterscotch, and butter. Cook on 70% (Roast) 5 minutes or until melted. Stir. fold in marhsmallows and nuts. Spread on buttered 13 x 9 inch pan. Refrigerate until set (about 2 hours). Cut into squares.