Preheat oven to 375 degrees.
Line square baking dish with parchment paper or spray glass baking dish with cooking spray.
In a large bowl, mix oats, baking powder, cinnamon, and salt.
Add in almond milk, maple syrup, egg (or egg substitute), coconut oil, vanilla, and mashed banana. Stir well to combine all the ingredients.
Gently fold in 1 cup of strawberries and blueberries as well as 1/2 of the bananas.
Bake in oven for about 55 minutes, until it bubbles and looks like the middle has set. Should be golden brown on the edges.
Remove from oven, and let it sit for a bit to cool down and set some more.