Generally cook your foodstuff in a single layer Until the recipe states that stacking is ok (like in these air fryer French fries and sweet potato fries recipes) Air fryers cook food quickly and evenly, because of the concentrated heat supply. The air fryer was invented by Philips in 2010. https://airfryer29639.onzeblog.com/30061801/top-cook-companion-air-fryer-secrets