Cocoa Banana Bars
These pretty, marbled bar cookies are very moist with a rich banana and chocolate flavor.
Set the oven to 350 degrees Fahrenheit (175 degrees C).
Butter a 9×13-inch baking dish.
Using an electric mixer, beat the butter and sugar in a sizable bowl until they are light and fluffy.
Beat in the egg and vanilla after adding them.
Add the reserved mashed banana after mixing.
Make a well in the center of the flour, baking soda, baking powder, and salt in a separate, large bowl.
Fill the well with the banana mixture, then stir just until combined.