1 box yellow cake mix
3 tbsp. peanut butter (heaping)
1 sq. semi-sweet chocolate
1 can milk chocolate frosting
1/4 c. chopped peanuts

Mix cake mix, as directed, beat in peanut butter. Stir in melted chocolate, in marble style. Bake in 13"x9" pan. Spread chocolate frosting over cool cake and sprinkle chopped peanuts on top.