01 - Place chicken breasts between two sheets of plastic wrap and gently pound to an even thickness of about 1/2 inch using a meat mallet.
02 - In a bowl, whisk together the buttermilk, salt, black pepper, and garlic powder. Add the chicken breasts, turning to coat evenly. Marinate for at least 30 minutes or up to overnight in the refrigerator.
03 - In a shallow bowl, combine the all-purpose flour, paprika, cayenne pepper, onion powder, salt, and black pepper until well blended.
04 - Pour vegetable oil into a large skillet to a depth of about 1/2 inch. Heat over medium-high heat until the oil reaches 350°F.
05 - Remove each breast from the marinade, allowing excess buttermilk to drip off. Dredge thoroughly in the seasoned flour mixture, pressing firmly to ensure the coating adheres on all sides.
06 - Carefully place the coated chicken into the hot oil, working in batches to avoid overcrowding. Fry for 6 to 7 minutes per side until golden brown and the internal temperature reaches 165°F.
07 - Transfer the fried chicken to a wire rack or paper towel-lined plate to drain excess oil. Let rest for 5 minutes before serving.