01 - Preheat oven to 350°F. Lightly grease two small ramekins or an oven-safe baking dish.
02 - In a medium bowl, mix together the rolled oats, cocoa powder, baking powder, and salt until well combined.
03 - In another bowl, whisk together the mashed banana, milk, maple syrup (or honey), and vanilla extract until smooth.
04 - Pour the wet ingredients into the dry ingredients. Stir until evenly combined. Fold in the chocolate chips and nuts if using.
05 - Divide the mixture evenly between the prepared ramekins. Sprinkle extra chocolate chips on top.
06 - Bake for 22 to 25 minutes, until the oats are set and the tops look slightly cracked.
07 - Let cool for 5 minutes. Serve warm, optionally with a drizzle of milk or a dollop of yogurt.