Slice the onion in half and then make "ribbons" about 1/8 inch thick. Separate all the onions and add them to a bowl.
3 cups onion
Pour milk over the onions and use a spoon to push down the onions so they're mostly covered by the milk. Let sit for 10-15 minutes.
1 cup coconut milk
Meanwhile, mix the dry ingredients in a lidded container. Set aside.
3/4 cup almond flour, 1/3 cup potato starch, 1/2 tsp sea salt, 1 tsp black pepper
Drain the onions, shaking the excess milk off. Place onions in the flour mixture. Put the lid on and shake until the onions are coated.
Preheat air fryer at 400 degrees F for 5 minutes.
Using clean hands, remove the onion from the flour mixture and set aside. In another bowl, add the olive oil. Add the onions to the olive oil and stir or shake to coat.
2 tsp olive oil
Lightly brush the inside of the air fryer with olive oil and add the onions. Cook for 8 minutes, and then shake the basket to distribute the onions.
Cook for another 5 minutes. Pro tip: spritz with olive oil on top to keep the onions extra crispy!
Continue to cook in 3-minute increments until it has reached your desired level of crispiness (took 20 minutes total for me).
Oven-Baked Instructions
Preheat oven to 425 degrees.
Follow steps 1-4 and 6 above.
For oven-baking, you'll need to use 1/4 cup olive oil.
Bake on rimmed baking sheet for 10 minutes. Stir, and bake an additional 10-15 minutes.
Notes
Onions can be made up to 2 days before serving. Allow the fried onions to fully cool before storing them in an air-tight container. Store at room temperature.