1Prepare cake batter and bake in 13x9-inch pan as directed on package; cool completely. Beat cream cheese and sugar in large bowl with mixer until well blended. Add peanut butter; mix well. Blend in 1 cup whipped topping; spread onto cake. Melt chocolate as directed on package. Mix with remaining whipped topping; spread over cake. Refrigerate 1 hour.
Looking for a dessert to serve at a party? Peanut butter and chocolate make a great combination in this cake that serves 24 people.