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, mash the ripe banana until smooth. Whisk in milk, maple syrup (or honey), and vanilla extract until fully incorporated.
04 - Pour wet ingredients into dry ingredients. Stir until just combined, being careful not to overmix. Fold in chocolate chips and nuts if using.
05 - Divide batter evenly between prepared ramekins. Sprinkle additional chocolate chips over the tops for extra chocolate flavor.
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 ramekins cool for 5 minutes before serving. Serve warm, optionally topped with a drizzle of milk or a dollop of yogurt.