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 blended.
03 - In a separate bowl, thoroughly whisk mashed banana, milk, maple syrup (or honey), and vanilla extract until smooth and uniform.
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 tops for extra melty goodness.
06 - Bake for 22-25 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 to set. Serve warm with a drizzle of milk or dollop of yogurt if desired.