Preheat oven to 350°F. Grease a 2-cup baking dish.
In a blender, blend banana, egg, milk, maple syrup, oats, salt, and baking powder until smooth.
Pour half of the mixture into the prepared baking dish.
Stir peanut butter and cocoa powder into the remaining mixture in the blender until smooth.
Pour the peanut butter mixture over the oats in the baking dish and use a fork to swirl it into the oat mixture.
Sprinkle chocolate chips on top.
Bake for 30-35 minutes, or until set.
Let cool slightly before serving.
