Preheat oven to 400 degrees F. Spray 12 cup muffin tin with nonstick 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 center 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.
Muffins are best served warm with your favorite spread. Feel free to add in chocolate chips, berries, or nuts to the batter!