Preheat oven to 350F. Spray 9x9 pan or 9 inch pie pan with non stick spray. Set aside.
In a bowl mix together oats and baking powder. In another bowl mash bananas, add all other ingredients and mix. Then combine the two to create your baked oatmeal batter.
If you choose to add 1/2 cup fresh/frozen blueberries or chocolate chips you can fold in now.
Pour into your dish and spread out so it is the same thickness across the pan (if you want to sprinkle top with crushed nuts you can now).
Bake in oven for 30 minutes for a moist texture or 35 minutes for a stiffer (can cut clean slices to serve) texture. Allow to cool for 15 minutes in the pan before serving.
It is great with a drizzle of maple syrup, heavy cream or squirt of whipped cream on top of each slice.