Start by setting up a simple breading station using three shallow bowls or pie plates, which will make the process much smoother and more organized. In the first bowl, whisk together half a cup of all-purpose flour with cornstarch. This dry blend forms the base layer, helping the batter stick to the onion rings while also contributing to a lighter, crispier texture.

In the second bowl, crack the eggs and add the buttermilk, then season the mixture with garlic powder, salt, and black pepper. Whisk everything thoroughly until the spices are evenly distributed. Next, add the remaining quarter cup of flour to the egg mixture and continue whisking until you get a smooth, slightly thick batter. This step ensures a flavorful and cohesive coating that clings well to each ring.

In the third bowl, add a generous amount of Panko breadcrumbs. These airy, flaky crumbs create that irresistible crunchy finish and are perfect for air frying because they brown beautifully without becoming greasy.

Take your onion and slice it into half-inch thick rounds. Then gently push out the center of each round to create individual onion rings. Be careful during this step to avoid breaking them, especially the larger outer rings. Once all the rings are separated, you’re ready to move on.

Before you start coating the onion rings, preheat your air fryer to 380 degrees Fahrenheit. Let it run for 5 minutes to ensure it reaches the proper temperature. This short preheating step is key to achieving a perfectly crisp and golden exterior.

As the air fryer preheats, begin breading the onion rings a few at a time to keep the process manageable and prevent clumping. First, dredge each ring in the flour and cornstarch mixture, making sure it's evenly coated, then gently shake off any excess flour to avoid a thick, gummy layer. Next, dip the ring into the egg and buttermilk mixture, turning it to coat all sides thoroughly. Let the extra batter drip off so the final coating adheres properly. Finally, press the onion ring into the Panko breadcrumbs, covering it completely to ensure a crisp, golden crust after cooking.

Arrange the coated onion rings in a single layer inside the air fryer basket, making sure they aren't stacked or overcrowded. If some rings are smaller, you can tuck them inside larger ones to save space, just be sure there’s enough airflow between them. Lightly spray the tops of the rings with oil spray to promote even browning and a crunchier texture.

Cook the onion rings in the air fryer at 380 degrees Fahrenheit for 10 to 12 minutes, or until they're golden brown and crisp. There’s no need to flip them during cooking, which keeps things quick and easy. Because most air fryers can't hold all the rings at once, you'll need to work in batches to avoid overcrowding.

Once a batch is done, you can serve the onion rings hot and fresh straight out of the air fryer. However, if you’d rather serve them all at once, place the cooked rings aside on a tray, and when the final batch is ready, return all of the rings to the air fryer. Heat them together for about 2 minutes to warm them through. This time, it’s fine to stack them, as you’re just reheating, not crisping.