In a large bowl, whisk together buttermilk, hot sauce, salt, garlic powder, and smoked paprika. Add chicken pieces, turning to coat. Cover and refrigerate for at least 2 hours, preferably overnight for deeper flavor.

In a shallow dish or large bowl, combine flour, cornstarch, smoked paprika, cayenne, onion powder, garlic powder, black pepper, and salt. Whisk thoroughly to distribute spices.

Remove chicken from marinade, letting excess drip off. Dredge each piece in the flour mixture, pressing firmly to adhere. Place on a wire rack set over a baking sheet and let rest for 10–15 minutes to allow the coating to set.

Pour oil into a large, heavy-bottomed skillet or Dutch oven to a depth of about 2 inches. Clip a deep-fry thermometer to the side and heat oil to 350°F (175°C). Maintain this temperature throughout frying.

Working in batches to avoid overcrowding, carefully lower 3–4 pieces of chicken into the hot oil. Fry for 12–15 minutes, turning once with tongs, until deeply golden brown and an instant-read thermometer inserted into the thickest part registers 165°F (74°C).

Transfer fried chicken to a clean wire rack set over paper towels. Do not cover (it steams the crust). Let rest for 5 minutes.

While chicken rests, combine honey, hot sauce, vinegar, and cayenne in a small saucepan over low heat. Stir gently until just warm and fluid, about 2 minutes. Do not boil.

Arrange chicken on a platter, drizzle generously with hot honey, and sprinkle with parsley. Serve immediately with suggested accompaniments.