Preheat your oven to 350°F (180°C). Line an 8x8-inch baking pan with parchment paper for easy removal.
In a large mixing bowl, mash the banana well. Add the applesauce, Greek yogurt, egg, peanut butter, and maple syrup. Whisk until smooth and well combined.
In a separate bowl, whisk together the baking powder, salt, cocoa powder, and flours. Stir in the chocolate chips.
Gradually fold the dry ingredients into the wet ingredients until you have a smooth, thick batter.
Spread the batter evenly in the prepared pan. Smooth the surface with a spatula.
Bake for approximately 30 minutes, or until a toothpick inserted in the center comes out clean.
Allow the brownies to cool completely before slicing into 12 pieces. For an extra treat, drizzle the top with melted peanut butter or chocolate. Enjoy!