Marinate the Chicken:
In a bowl, whisk together buttermilk and hot sauce. Add chicken breasts and let soak for at least 30 minutes (or overnight in the fridge for best flavor).
Prepare the Breading:
In a shallow dish, mix flour, cornstarch, paprika, garlic powder, onion powder, salt, and pepper.
Dredge the Chicken:
Remove chicken from marinade and let excess drip off. Dredge each piece in the seasoned flour mixture, pressing to coat well. Let rest on a rack while you heat the oil.
Fry the Chicken:
Heat ½ inch of oil in a large skillet over medium heat. Once hot (350°F), fry chicken for 3–4 minutes per side or until golden brown and cooked through. Drain on paper towels or a wire rack.
Make the Gravy:
In a clean pan or using 3 tablespoons of pan drippings, whisk in flour and cook for 1–2 minutes. Slowly whisk in milk and simmer, stirring constantly, until thickened. Season with salt, pepper, and cayenne if desired.
Serve:
Spoon warm gravy over crispy chicken. Serve with mashed potatoes, biscuits, or green beans.