Preheat the oven to 350°F (175°C) and grease a baking dish.
In a large bowl, mix the milk, eggs, maple syrup, melted butter, and mashed banana until well combined.
Add the oats, baking powder, and cinnamon. Stir until evenly distributed.
Gently fold in the mixed berries and chopped nuts (if using).
Pour the oat mixture into the prepared baking dish.
Bake for 40-45 minutes until the center is set and a toothpick comes out clean.
If desired, serve warm with ½ cup of milk and two tablespoons of almond butter topping.
Notes
More Protein: Add 2-3 scoops of collagen powder or hard-boiled or scrambled eggs on the side for an extra protein boost.
Toppings: Feel free to add your favorite nut butter, fruit, coconut shreds, or additional nuts/seeds.
Leftovers: Store in an airtight container in the refrigerator for 5-7 days. Reheat each serving as needed.