In a large bowl, whisk together the oil, eggs, applesauce, maple syrup, and cider.
Add the oat flour, cinnamon, baking soda, baking powder and salt. Stir until well incorporated.
Add the chopped apple, stirring until just combined.
Fill each section of a 12-section greased or lined muffin tin with roughly ¼ cup batter.
Sprinkle with cinnamon sugar, if using, then bake for 15-20 minutes, or until the edges begin to pull away from the sides and a toothpick comes out clean.
Allow to cool completely in the pan, then serve or store for later.
Notes
For gluten-free, be sure to use gluten-free oat flour.
These muffins are super tender, so be sure to grease or line the muffin tin, and allow to cool completely for easy removal.
Not a fan of chunks? Try grating the apple for a smoother consistency.