Preheat the oven to 180°C. Line six hollows of a deep muffin tin with baking paper and grease well with non-stick spray.
1. Sift the flour, baking powder, bicarbonate of soda, salt and cocoa powder together, then add the oats and sugar. Mix well.
2. Mix the mashed bananas with the eggs, oil, orange zest and juice. Fold lightly into the dry ingredients until just mixed.