Spray loaf pan with cooking spray and set aside. In a large bowl, whisk Lorraine's GF All Purpose Flour, baking powder, baking soda and salt, set aside. In a blender, add bananas, oil, sugar, eggs, and vanilla extract and blend until smooth.  Add blended banana mixture into the flour mixture.  Stir until combined.  Fold in chocolate chips and nuts if using. Pour batter into the prepared loaf pan and top with more chocolate.  Bake for 50 minutes to 1 hour, or until a toothpick inserted into the center of the loaf comes out clean. If desired, tent with aluminum foil half way to prevent too much browning. Let bread cool into the pan for 10 minutes, then turn out onto a wire rack.