Prep the onions. Peel the onions and slice them into 1/2-inch thick rounds. Gently separate into rings. Save the tiny center pieces for sautéing another time.

Set up a dredging station. In one shallow bowl, whisk flour, cornstarch, baking powder, salt, pepper, garlic powder, and paprika. In a second bowl, beat eggs with buttermilk. In a third bowl, add breadcrumbs (stir in Parmesan or cayenne if using).

Preheat the air fryer. Set it to 380°F (193°C) for 5 minutes. A hot basket helps the coating set and crisp quickly.

Coat the rings. Working a few at a time, dredge onion rings in the flour mixture, shaking off excess. Dip into the egg mixture, letting extra drip off. Press into breadcrumbs until fully coated. Place coated rings on a tray while you work.

Oil lightly. Spray both sides of the coated rings with cooking oil. Don’t soak them—just a light, even mist helps browning and crunch.

Air fry in batches. Arrange rings in a single layer in the basket without crowding. Air fry at 380°F (193°C) for 8–10 minutes, flipping halfway and spraying again lightly if any dry spots appear. They’re done when golden brown and crisp.

Season and serve. Sprinkle with a pinch of salt right out of the air fryer. Serve hot with your favorite dipping sauce.