Preheat the oven to 375° F.
In a large bowl combine the oats, cinnamon, baking powder and salt.
In a separate mixing bowl, mash the bananas, then add the almond milk, peanut butter, applesauce, and vanilla extract. Stir until well combined and few to no lumps remain.
Combine wet and dry ingredients.
Pour into an 8x11 baking pan.
Bake uncovered until the top of the oatmeal is golden and the mixture is set, about 30 minutes. Remove and allow oatmeal bake to cool for 5 minutes.
Slice into 8 servings. Serve with drizzled peanut butter and banana slices, if desired.