Preheat the air fryer to 265F (130 C) for 5 minutes.
Lightly spray air fryer basket with oil, then add the sliced onions to the basket and spray them gently with oil and toss to coat evenly.
Cook in the air fryer for 25-30 minutes total, setting a timer for every 5 minutes to shake the basket and toss the onions around. Once golden brown and crispy, onions are ready.
Allow fried onions to cool completely before storing in an air tight jar in the fridge for up to one month.
Video
Notes
You can use red, white or yellow onions and even shallots instead of onions.