Start by heating vegetable oil in a deep fryer or large pot to 350°F (175°C).

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

For efficiency, arrange three bowls: one with buttermilk, the second with flour mixture, and the last with panko breadcrumbs.

Gently dip each onion ring into the buttermilk, dredge it in the flour mixture, dip again in the buttermilk, and coat with panko.

Carefully add the coated onion rings to the hot oil in small batches. Fry for 2–3 minutes until golden brown.

Remove the onion rings and place them on a paper towel-lined plate to drain excess oil. Serve warm.