black bottom banana bars

1/2 cup butter, softened (i use oil)
1 cup sugar (i use a half cup - they are still super good)
1 egg
1 tsp vanilla extract
3 ripe bananas, mashed
1 1/2 cups all-purpose flour
1 tsp baking powder
1 tsp baking soda
1/2 tsp salt
1/4 cup baking cocoa

in a mixing bowl, combine butter, sugar, egg, vanilla and bananas. mix dry ingredients (not cocoa) and add to the wet. divide batter in half. add cocoa to half and spread into greased 9x13 pan. spoon remaining batter on top and swirl with a knife. bake at 350 for 25 minutes or until bars test done.

note: these are goo-ood. a nice change from banana bread when you have bananas that need to be used up. just like the pioneers.

from taste of home magazine