1. Preheat oven to 350F (180C).
2. Make oat flour. Add oats to a blender or food processor. Blend until oats have turned into a fine flour.
3. In a large bowl, combine oat flour, baking powder, baking soda, cinnamon and salt.
4. In a medium bowl, whisk together eggs, Greek yogurt, honey, apple sauce, vanilla extract and ghee.
5. Add wet ingredients to the dry ingredients, stir well. Add grated apple and diced apple, stir.
6. Divide the batter between muffin cups (I had 15 silicone muffin cups and left some space at the top, to make smaller muffins for kids. If you fill all the way to the top, you’ll get about 12 muffins).
7. Bake in the preheated oven for 20-25 minutes, until a toothpick inserted in the center comes out clean.