Preheat oven to 350, and line an 8x8 baking pan with parchment paper, or grease the pan. 2. In a medium mixing bowl, whisk rice flour, tapioca starch, brown sugar, salt and baking powder to combine. 3. Add beaten eggs, oil, peanut butter and mashed bananas to the bowl with the dry ingredients and stir until well incorporated. 4. Fold in chocolate chips. 5. Pour batter into baking pan and bake for 25-30 minutes, or until a toothpick inserted in the center comes out clean. Allow to cool for at least one hour before serving. Slice into 9 equal squares.