Heat a dutch oven over medium heat with 1 inch of oil (or enough to submerge the onion rings). A deep fryer works too if available.

In a medium bowl, mix together 1 cup of milk with 1 Tbsp of vinegar and let it sit for 5 minutes. Whisk in 1/2 cup of sour cream.

In a separate bowl, combine 1 cup of flour, 1/2 Tbsp of salt, 1/4 tsp of pepper, and 1 tsp of garlic powder.

Separate the onion slices into individual rings. Dip each ring into the milk mixture, then coat it with the flour mixture. For cleaner hands, use a fork to transfer the rings from the wet to the dry mixture. Dip again in the milk mixture and dredge once more in the flour. Set the coated rings aside on a plate until ready to fry.

Heat the oil to 375°F, ensuring it’s hot enough for the onion rings to sizzle upon contact. Fry 3-4 double-battered onion rings at a time, cooking for about 3 minutes, turning them halfway through, until they are crisp and light golden brown. Drain the fried onion rings on paper towels to remove excess oil.