1 (14 oz.) can sweetened condensed milk
2 tbsp. butter
1 (12 oz.) pkg. semi-sweet chocolate pieces
1/2 lb. (1 2/3 c.) unsalted roasted peanuts
1 (10 oz.) pkg. mini-marshmallows

Mix sweetened condensed milk, butter and chocolate pieces in a large glass bowl. Microwave at 50% power for 3 minutes. Stir well. Microwave at 50% for 1 minute longer if mixture has not completely melted.

In a large bowl combine peanuts and marshmallows. Fold in melted chocolate mixture. Line sides and bottom of a 9 x 13 x 2 inch pan with wax paper. Spread candy in pan. Chill for 2 hours or until firm. Peel off wax paper. Cut in 1 inch squares. Wrap in plastic wrap.