Preheat oven to 350º and grease a 9 x13 inch pan with cooking spray. Combine cocoa powder, milk, melted butter and banana in a small bowl.

Combine oatmeal, flour and sugar in a mixing bowl, mix well. Add wet ingredients into flour mixture, stir until well incorporated.

Spoon into prepared pan, and level the top with a back of a spoon or spatula. Bake for 25 minutes or until a skewer inserted comes out clean. Let sit in the pan for 5 minutes, slice while they are still warm. Enjoy!!