Preheat the oven to 160°C / 140°C (fan oven) / 320°F / Gas Mark 3. Mist a muffin tin with cooking spray. In a large bowl, mash the banana until smooth. Add the coconut milk, egg, and maple syrup and whisk until combined. Add the porridge oats and baking powder, whisk again until combined, then fold in the blueberries.

Spoon the mixture into the prepared tin, filling three-quarters of the way up. Scatter over the coconut flakes. Baking for 25 minutes or until set and the coconut is golden. Cool in the tin for 5 minutes, then cool further on a cooling rack. Eat warm or cold.