01 - Whisk buttermilk with salt, garlic powder, onion powder, cayenne, and black pepper in a large bowl. Submerge chicken pieces completely. Cover and refrigerate for 2 hours minimum, preferably overnight.
02 - Combine flour, paprika, salt, black pepper, cayenne, and baking powder in a separate bowl until evenly blended.
03 - Remove chicken from marinade, allowing excess to drip off. Press each piece firmly into flour mixture, ensuring thick, even coverage. Arrange on rack and rest for 10 minutes.
04 - Heat vegetable oil in deep fryer or heavy pot to 350°F.
05 - Lower chicken pieces into hot oil in batches, avoiding overcrowding. Fry for 12-15 minutes, turning occasionally, until golden brown and crisp with internal temperature reaching 165°F.
06 - Transfer chicken to wire rack or paper towels to drain. Allow to rest for 5 minutes before serving.