01 - Set out three shallow bowls. In the first bowl, combine flour, salt, and black pepper. In the second bowl, beat eggs with milk until smooth. In the third bowl, mix panko breadcrumbs with paprika, garlic powder, and Parmesan cheese if using.
02 - Dredge each onion ring in the seasoned flour, ensuring each piece is evenly coated. Dip into the egg mixture, then press gently into the breadcrumb mixture until fully coated. Transfer coated rings to a tray or plate.
03 - Preheat the air fryer to 375°F (190°C) for 3 minutes before cooking.
04 - Lightly spray both sides of the breaded onion rings with cooking spray for an even crisp. Place rings in a single layer in the air fryer basket. Work in batches to avoid overcrowding.
05 - Cook onion rings for 8 to 10 minutes, flipping halfway through, until golden brown and crisp. Remove from the basket and repeat with remaining rings if necessary.
06 - Serve onion rings immediately, accompanied by ketchup, ranch, or preferred dipping sauce.