Peel onion and cut it into ½-inch thick slices. Separate the slices and place them on a plate. Set aside.

In a wide, shallow bowl, lightly beat the eggs with the buttermilk until well combined. In a second bowl, combine the flour, salt, pepper, and garlic powder. Place the panko bread crumbs in a third bowl.

Dip each onion ring into the flour, then the buttermilk mixture, and then dredge it through the bread crumbs, pressing to adhere. Set aside on a baking sheet and repeat with remaining rings. Spray the rings with an EVO Oil sprayer.

Transfer the rings into the air fryer basket in a single layer, nesting the smaller ones inside the larger ones but leaving a little space between each ring. Don’t overcrowd the basket, and work in batches if necessary. 

Air fry for 9-12 minutes, or until golden brown and crispy. 

Sprinkle with salt if desired, and serve.