01 - Combine buttermilk, salt, black pepper, paprika, and garlic powder in a large bowl. Coat chicken pieces thoroughly, cover, and refrigerate for at least 2 hours or overnight for optimal flavor.
02 - In a separate shallow dish, whisk together all-purpose flour, salt, paprika, cayenne pepper, baking powder, and black pepper until evenly blended.
03 - Remove chicken from marinade, letting excess drip off. Dredge each piece in the flour mixture, pressing firmly to adhere. For added crispness, dip the chicken back into buttermilk and dredge again in the flour mixture.
04 - Preheat vegetable oil in a deep fryer or heavy pot to 350°F (175°C). Use a thermometer to maintain temperature accuracy.
05 - Fry chicken in batches without overcrowding for 12 to 15 minutes. Turn pieces occasionally until golden brown and internal temperature reaches 165°F (75°C).
06 - Transfer fried chicken to a wire rack over a baking sheet or paper towels to drain excess oil. Allow to rest for 5 minutes before serving.