1⁄2 cup butter, softened
1 cup sugar
1 teaspoon vanilla extract
1 1⁄2 cups mashed ripe bananas (about 3 medium)
1 1⁄2 cups all-purpose flour
1 teaspoon baking powder
1 teaspoon baking soda
1⁄2 teaspoon salt
1⁄4 cup baking cocoa
1/2 cup chocolate chips
Add cream butter and sugar in a large mixing bowl. Add egg and vanilla; beat until thoroughly combined. Blend in the bananas.
In a separate bowl, combine the flour, baking powder, baking soda and salt; add to creamed mixture and mix well.
Divide batter in half. Add and mix cocoa to half and spread into a greased 13-in x 9-in pan. Fold in chocolate chips to the remaining half and spoon batter on top of first layer. Swirl with a knife.
Bake at 350 degrees for 25 minutes or until cake tester comes out clean when inserted in the center. Cool completely before cutting into bars. Makes 24 bars. Serve as is or with a scoop of vanilla ice cream.