Preheat the oven to 180°C (356°F).
Mash the banana and mix it with the egg.
Mix cocoa powder, almond flour, and baking powder evenly.
Combine all ingredients to form a batter.
Pour the batter into an oven-safe container.
Bake at 180°C (356°F) for 20-25 minutes.
Let it cool before eating.