01 - In a large bowl, whisk together the buttermilk, salt, black pepper, paprika, garlic powder, onion powder, and cayenne pepper.
02 - Submerge the chicken pieces in the marinade, cover, and refrigerate for at least 4 hours, preferably overnight.
03 - In a separate bowl, mix the flour, salt, black pepper, paprika, cayenne pepper, and baking powder.
04 - Heat vegetable oil in a deep fryer or large heavy-bottomed pot to 325°F (160°C).
05 - Remove chicken pieces from the marinade, letting the excess drip off. Dredge thoroughly in the flour mixture, pressing gently to adhere.
06 - Fry the chicken in batches, avoiding overcrowding, turning occasionally until golden brown and cooked through (internal temperature of 165°F/74°C), about 15–18 minutes.
07 - Drain on a wire rack set over a baking sheet.
08 - Let rest for 5 minutes before serving for maximum juiciness.