1. Preheat your oven to 180c and line a tray with baking paper.
  2. In a bowl, combine the mashed banana, coconut oil and maple syrup and cream these together.
  3. Beat in both of the eggs until everything is well combined.
  4. Fold through the dry ingredients, then add in the blueberries.
  5. Transfer into the baking dish and smooth over the surface.
  6. Top with your favourite chocolate and bake in the oven for 15-20 minutes.
  7. Allow to cool slightly, then slice into squares.