Slice a large onion into ½-inch thick rings, separating them carefully. Set aside.

In a shallow dish, whisk together buttermilk and beaten egg until smooth.

In another bowl, mix all-purpose flour, cornstarch, smoked paprika, salt, black pepper, and garlic powder.

Pour panko breadcrumbs into a third shallow dish.

Dredge each onion ring in the flour mixture, then dip in the buttermilk mixture, and finally coat with panko breadcrumbs.

Place the coated onion rings on a wire rack or parchment paper to rest for 10-15 minutes.

Heat about one inch of oil in a skillet to 350°F - 375°F.

Fry onion rings in small batches for 2-3 minutes until golden brown.

Use a slotted spoon to remove the fried onion rings and drain on a wire rack.