Preheat oven to 350. Lightly grease a 12 piece muffin pan or line with paper liners and set aside.
In a large bowl, combine the oats, oat flour, baking powder, baking soda, salt, and cinnamon.
In a small bowl, whisk together the milk, maple syrup, apple sauce, eggs, apples, and vanilla.
Pour the wet mixture into the flour mixture and mix until combined. Do not overmix.
Evenly scoop batter into the prepared muffin pan. Sprinkle tops of muffins with oats if desired.
Bake for 15-18 minutes, or until toothpick entered in center of muffin comes out clean.
Let cool and remove from pan.
Enjoy!