Preheat oven to 400 degrees F.
In a large bowl, combine the oats, flour, brown sugar, baking powder, baking soda, cinnamon, and salt.
In another bowl, combine the applesauce, milk, coconut oil, and egg whites. Stir this mixture into the dry ingredients. Combine until just moistened. Gently fold the diced apples into mixture.
Fill muffin cups (or muffin tin sprayed with non-stick spray) 3/4 full.
Bake for 16-18 minutes, or until toothpick comes out clean. Cool on a cooling rack.