Preheat oven to 350 degrees
Grease donut pan and dust with coconut flour
Mix diced apple with stevia packet and cinnamon
Heat coconut oil in skillet and cook apples
Pulse almond flour, flax meal, coconut flour, baking soda, and salt in food processor
Add eggs, vinegar, half of the cooked apples, and vanilla stevia and process until combined
Place batter and rest of cooked apples in Ziploc back, snip off corner, and pipe into donut pan
Bake for 20-25 minutes or until toothpick inserted into center comes out clean
Remove from oven and allow to cool in pan for 1 hour