Preheat oven to 375 degrees F and spray non-stick 12 muffin tin with cooking spray. Set aside.In a large mixing bowl, lightly beat the egg. Add bananas and mash well. Add remaining ingredients, except flour, and whisk to combine. Now add flour and gently stir until well incorporated. Do not over mix otherwise muffins will be tough.Fill each tin almost full with batter (I used regular ice cream scoop) and bake for 22 minutes or until a toothpick inserted in the centre comes out clean. Let muffins cool for about 5 minutes and transfer to a cooling rack to cool off completely.