01 - Preheat your oven to 350°F. Lightly grease two small ramekins or an oven-safe baking dish with cooking spray or a small amount of oil.
02 - In a medium bowl, mix together the rolled oats, cocoa powder, baking powder, and salt until evenly distributed.
03 - In a separate bowl, whisk together the mashed banana, milk, maple syrup (or honey), and vanilla extract until smooth and well combined.
04 - Pour the wet ingredients into the dry ingredients. Stir until just combined, being careful not to overmix. Fold in the chocolate chips and nuts if using.
05 - Divide the batter evenly between the prepared ramekins. Sprinkle additional chocolate chips on top for extra richness.
06 - Bake for 22 to 25 minutes, or until the oats are set and the tops appear slightly cracked. A toothpick inserted into the center should come out mostly clean.
07 - Allow the baked oats to cool for 5 minutes before serving. Enjoy warm, optionally drizzled with additional milk or topped with a dollop of yogurt.