01 - Preheat 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, whisk together rolled oats, cocoa powder, baking powder, and salt until evenly distributed.
03 - In a separate bowl, thoroughly whisk mashed banana, milk, maple syrup (or honey), and vanilla extract until smooth and well combined.
04 - Pour wet ingredients into dry ingredients and stir until just combined. Gently fold in chocolate chips and nuts if using. Do not overmix.
05 - Divide batter evenly between prepared ramekins. Sprinkle additional chocolate chips over the surface for extra richness.
06 - Bake for 22 to 25 minutes until oats are set and tops appear slightly cracked. A toothpick inserted in the center should come out mostly clean.
07 - Let cool for 5 minutes before serving. Enjoy warm, optionally drizzled with additional milk or topped with a dollop of yogurt.