Preheat oven to 180°c. Line a 12-hole muffin tray with paper cases.
Blend spinach leaves in a blender until finely chopped. Add bananas, vegetable oil, egg, and honey, blending until smooth. Transfer to a bowl and stir in milk, flour, baking powder, and bicarbonate of soda.
Spoon into cases. Bake for 25 minutes or until cooked and golden.