CHOCOLATE LAYER:

1 box chocolate cake mix
1 stick unsalted butter, softened
1 1/4 cup buttermilk
4 large eggs

BANANA LAYER:

2 1/4 cups bisquick
1 cup mashed ripe bananas
1/4 cup sugar
1/3 cup milk
1 egg
1 teaspoon pure vanilla
2 tablespoons unsalted butter, softened

FROSTING:

1 cup creamy peanut butter
1 stick unsalted butter, softened
1 cup confectioners sugar
1 tablespoon light brown sugar
1/2 teaspoon milk (if needed)

preheat oven to 375°. line 2 cupcake pans with liners and set aside.

in a large bowl, combine all ingredients to make the chocolate layer. beat on medium speed until no longer lumpy and well blended; set aside. add the confectioners sugar and brown sugar. beat until light and fluffy, adding milk if needed.

in another bowl, combine all ingredients to make banana layer. beat on medium speed until well blended. spoon banana layer into cupcake tins about 1/3 of the way full. top with chocolate layer until tins are 2/3 full. bake for 25 minutes or until toothpick inserted into center of cupcake comes out clean. cool in pan for 5 minutes then transfer to wire rack to cool completely.

to make frosting: cream together the butter and peanut butter until light and creamy.