Preheat the oven to 375 degrees F (180 degrees C). Grease or line a 12-cup muffin tin with paper liners.
Use a blender or food processor to blend oats into oat flour. Mix in cinnamon, nutmeg, baking powder, and salt.
Mix apples, applesauce, almond milk, oil, and vanilla together in a large bowl until combined. Slowly add the oat mixture, mixing until thick like cookie dough. Add even spoonfuls of the mixture to the muffin tins.
Bake in the preheated oven until tops spring back to the touch, 14 to 18 minutes. Let cool at least 5 minutes before serving.