Prepare the Onion Rings:

Peel the onion and slice it into rings about 1/4-inch thick. Separate the rings and set aside.

Set Up the Breading Stations:

In the first bowl, add the flour.

In the second bowl, whisk the eggs.

In the third bowl, combine the breadcrumbs, Parmesan cheese (if using), garlic powder, smoked paprika, salt, and black pepper.

Bread the Onion Rings:

Dip each onion ring into the flour, shaking off any excess. Then, dip it into the egg mixture, ensuring it's fully coated. Finally, press it into the breadcrumb mixture, coating evenly.

Preheat the Air Fryer:

Preheat your air fryer to 375°F (190°C) for 5 minutes.

Cook the Onion Rings:

Lightly spray the air fryer basket with olive oil. Arrange the breaded onion rings in a single layer without overlapping. Spray the tops of the rings lightly with olive oil.

Cook at 375°F (190°C) for 8–10 minutes, flipping halfway through, until golden brown and crispy.

Serve:

Remove the onion rings from the air fryer and serve immediately with your favorite dipping sauces, such as ketchup, ranch, or spicy mayo.