Prep the onions: Peel onions and slice into 1/2-inch rings. Gently separate rings.
Pat dry with paper towels to help the coating stick.
Set up dredging stations: In one shallow bowl, whisk eggs with 1 tablespoon heavy cream or almond milk. In a second bowl, mix 1/2 cup almond flour, 1 cup finely crushed pork rinds, 1/4 cup grated Parmesan (if using), 1 teaspoon smoked paprika, 1 teaspoon garlic powder, 1/2 teaspoon onion powder, 1/2 teaspoon salt, and 1/4 teaspoon black pepper.
Preheat the air fryer: Set to 375°F (190°C) for 5 minutes. A hot basket helps the coating crisp right away.
Coat the rings: Dip each onion ring into the egg wash, let excess drip off, then press into the crumb mixture.
Press firmly to coat all sides. For extra crunch, repeat the egg and crumb step once more for a double-coat.
Spray and arrange: Lightly spray the air fryer basket with oil. Place rings in a single layer without overlapping.
Mist the tops of the rings with a light spray of oil for better browning.
Air fry: Cook at 375°F for 8–10 minutes, flipping halfway and spraying again lightly after flipping. They’re done when deeply golden and crisp.
Work in batches: Don’t crowd the basket. Keep finished rings on a wire rack so they stay crisp while you finish the rest.
Season and serve: Taste and add a pinch of salt if needed.
Serve hot with your favorite low-carb dips.