Chocolate Peanut Butter Cake

Directions

1. Prepare and bake cake according to package directions, using a greased 13-in. x 9-in. baking pan.
2. In a small bowl, combine peanut butter and oil until smooth; spread over warm cake. Cool completely on a wire rack.
3. In a microwave, heat frosting on high for 25-30 seconds or until pourable; stir until smooth. Carefully pour and spread over peanut butter layer. Let stand until set.