1/2 cup butter or margarine -- softened
1 cup sugar
1 egg
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

In mixing bowl, cream butter and sugar. Add egg and vanilla; beat til thoroughly combined. Blend in the bananas. Combine the flour, baking powder, baking soda and salt; add to creamed mixture and mix well.

Divide batter in half. Add cocoa to half; spread into greased 13 x 9 in x 2 inch baking pan. Spoon remaining batter over top and swirl with a knife.

Bake at 350 for 25 minutes or til bars test done. Cool.

Yield 2 1/2 to 3 dozen.

Stacy's Notes - have made these many times. An old favorite. They are crumbly and very hard to cut evenly, so they don't make a very good presentation bar to take to a function. But they taste delicious and we eat them at home! :)