Preheat oven to 200 degrees. Spray 12 cup muffin tin with non-stick cooking spray or grease well with coconut oil
In a medium bowl whisk together oat bran, protein powder, baking powder and cinnamon; set aside.
In a large bowl, mix mashed banana, applesauce, Greek yogurt, egg whites, and vanilla together until well combined and smooth. Add wet ingredients to dry ingredients and mix until just combined. Let batter sit two minutes to thicken a bit.
Divide batter evenly into 12 muffin cups and bake 15 minutes or until toothpick inserted into centre comes out clean. Transfer to a wire rack to cool for 10 minutes, then remove muffins from tin and place on wire rack to cool completely.