Top and tail the onions and peel the skin off, then cut them into thick rings about an inch thick. Use your hands to push them apart so that you have a single layer of onion in a ring.
– Prepare your dipping bowls by whisking together the egg and buttermilk in one bowl, the flour, salt, pepper, and spices in another, and the panko crumbs in another. Line up your three bowls.
Preheat your air fryer to 350°F.
Use a fork or clean hands to dip the onion rings into the flour mix, then the egg mix, then the panko mix.