Begin by heating vegetable oil in a deep fryer or a large pot until it reaches 350°F (175°C). Prepare your frying area with paper towels nearby.

In a medium bowl, combine all-purpose flour, garlic powder, paprika, salt, and freshly ground black pepper. Whisk until smooth and well-blended.

Pour buttermilk into a separate shallow bowl to help the flour mixture stick to the onion rings.

Dip each onion ring into the buttermilk, then coat generously in the flour mixture, pressing lightly to ensure good adhesion.

For added crunch, dip each floured onion ring back into the buttermilk and then dredge in panko breadcrumbs, pressing firmly.

Carefully place the coated onion rings into the hot oil, frying in batches for about 2-3 minutes until golden brown.

Remove the fried onion rings from the oil using a slotted spoon and transfer to a plate lined with paper towels.