In a large bowl whisk together flours, brown sugar, baking powder, baking soda, cinnamon and salt. Set aside. In a separate medium bowl, lightly beat milk, egg, peanut butter and mashed banana together. Add the wet ingredients to the dry ingredients. Let sit for 5 minutes.
Heat a large skillet or griddle over medium high heat. Lightly grease with butter or nonstick cooking spray.
Pour pancake batter 1/4 cup at a time into skillet and cook pancakes until bubbles form on top. Flip pancakes, cook for 1 minute, then remove to a plate. Place in a warm oven until ready to serve. Repeat as necessary.
Serve with maple syrup and additional banana slices, if desired.