Preheat the oven: Set your oven to 350°F (175°C) and grease two small ramekins or an oven-safe dish.
Blend the oats: In a blender, pulse the oats until they turn into a fine flour. If you prefer a more textured oatmeal, skip this step.
Mix the wet ingredients: In a bowl, mash the banana, then mix in the egg, milk, maple syrup, and vanilla extract.
Combine everything: Add the blended oats, baking powder, salt, and cinnamon (if using) to the wet ingredients. Stir until smooth.
Pour into ramekins: Divide the batter between the two ramekins and smooth the tops.
Add toppings: Sprinkle chocolate chips, berries, nuts, or any toppings you like.
Bake: Place the ramekins in the oven and bake for 20-25 minutes, or until the tops are golden brown and a toothpick inserted in the center comes out clean.
Cool and enjoy: Let the baked oats cool for a few minutes before digging in. Serve warm and enjoy!