01 - Combine buttermilk and hot sauce in a large bowl. Submerge chicken pieces completely, cover, and refrigerate for minimum 30 minutes or up to 8 hours for optimal flavor penetration.
02 - Mix flour, paprika, garlic powder, onion powder, salt, black pepper, and cayenne in a shallow bowl until thoroughly combined.
03 - Remove chicken from marinade, allowing excess liquid to drip off. Press each piece firmly into seasoned flour mixture, ensuring complete coating. Transfer to wire rack.
04 - Heat 1 inch vegetable oil in heavy skillet to 350°F. Fry chicken in batches without overcrowding, cooking 8–12 minutes per side until golden brown and internal temperature reaches 165°F. Drain on paper towels.
05 - Preheat oven to 425°F for biscuit baking.
06 - Whisk flour, baking powder, baking soda, salt, and sugar. Cut in cold butter using pastry blender or fingers until mixture resembles coarse crumbs. Stir in buttermilk until just combined.
07 - Turn dough onto floured surface, pat gently to 1-inch thickness. Cut rounds using biscuit cutter or glass. Place on baking sheet and brush tops with buttermilk.
08 - Bake for 12–15 minutes until golden brown and cooked through.
09 - Melt butter in saucepan over medium heat. Whisk in flour, cooking for 2 minutes while stirring constantly to remove raw flour taste.
10 - Gradually whisk in milk, continuing to stir for 5–7 minutes until sauce thickens. Season with black pepper and salt.
11 - Place warm biscuits on plates, top with fried chicken pieces, and ladle gravy generously over chicken and biscuits.