Rinse the beef chitterlings thoroughly under cold running water, making sure to remove any grit. Trim away any large pieces of fat or tough membranes for a cleaner bite.

In a large mixing bowl, combine the buttermilk, vinegar, salt, pepper, garlic powder, and onion powder. Stir to blend. Submerge the chitterlings in the seasoned marinade, ensuring each piece is well-coated. Cover and refrigerate for at least 2 hours, or preferably overnight, to tenderize and flavor the meat.

In a separate bowl, whisk together the flour, cornstarch, and paprika. Remove the chitterlings from the marinade, allowing any excess to drip off. Dredge each piece in the flour mixture, pressing gently to ensure an even, crisp coating.

Heat oil in a deep fryer or heavy-bottomed pot to 350°F (175°C). Working in small batches, carefully lower the coated chitterlings into the hot oil. Fry each batch for approximately 3 to 5 minutes, or until they are golden brown and crispy. Avoid overcrowding to maintain the oil temperature and achieve an even fry.

Use a slotted spoon to transfer the fried chitterlings to a paper towel-lined plate to drain excess oil. Serve hot with your favorite dipping sauce or classic Southern sides like coleslaw, fried okra, or cornbread.