Preheat your oven to 350F.
Mash the bananas at the bottom of a baking dish (I used an 8x8, but any similar-sized dish works!).
Add oats, chia seeds, milk, and protein powder (if using), then mix everything together.
Sprinkle frozen berries, chocolate chips, and shredded coconut on top.
Bake for 25 minutes.
Remove from the oven, let it cool for a bit, and enjoy your delicious baked oatmeal!