Preheat the oven to 400°F.
In a large bowl, whisk together oats, flour, brown sugar, baking powder, baking soda, and cinnamon.
In another medium bowl, whisk together applesauce, milk, oil and the egg white.
Once combined, transfer the wet ingredients onto the dry ingredients. Mix just until the dry ingredients are moistened.
For the topping, mix together oats, brown sugar, cinnamon, and butter in a small bowl.
Place a 12 cup muffin pan in the preheated oven for a couple minutes, then remove and butter or spray with non-stick spray.
Fill the pan evenly with the batter. Distribute the topping evenly on top of the muffins.
Bake 20-22 minute or until a toothpick inserted comes out clean.