01 - Preheat oven to 350°F. Lightly grease two small ramekins or an oven-safe baking dish with cooking spray or butter.
02 - In a medium bowl, whisk together rolled oats, cocoa powder, baking powder, and salt until evenly distributed.
03 - In a separate bowl, mash the ripe banana thoroughly. Add milk, maple syrup (or honey), and vanilla extract. Whisk until smooth and creamy.
04 - Pour wet ingredients into dry ingredients. Stir until just combined, being careful not to overmix. Gently fold in chocolate chips and nuts if using.
05 - Divide batter evenly between prepared ramekins. Sprinkle additional chocolate chips over the surface for an extra chocolatey finish.
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 moist but not wet.
07 - Let ramekins cool for 5 minutes to set. Serve warm, optionally topped with a drizzle of milk or a dollop of yogurt.