Cut whole chicken into 10 pieces (or more), rinse, and pat dry.
Place the chicken pieces on a board or in a large bowl, and season with salt and Creole seasoning.
Make the buttermilk marinade by mixing the buttermilk and hot sauce in a large bowl. Gently whisk until thoroughly combined. Transfer the seasoned chicken to the buttermilk marinade, coat the chicken well, cover the bowl with plastic wrap, and marinate the chicken for 4 hours or overnight in the fridge.
On a large plate, mix the flour, cornstarch, paprika, Creole seasoning, garlic powder, onion powder, dried thyme, bouillon powder, cayenne pepper, black pepper, and salt until combined.
Remove the chicken one piece at a time from the buttermilk marinade, letting the excess drip back into the bowl. Then, dredge it in the flour mixture, pressing it into the seasoned flour until it adheres to all sides of the chicken. Then, shake off the excess flour. A gallon-sized ziplock bag works for this process, too.
Transfer the coated chicken to a tray and let it rest for 10-15 minutes while heating the oil. That also helps the coating stay on better.
Heat the oil in a deep fryer or cast iron skillet to 375℉/190℃.
Using tongs, slowly and carefully place the chicken in the hot oil. Remember, the temperature will drop once you add chicken, so work in batches to avoid overcrowding the skillet and lowering the oil temperature too quickly.
Fry the chicken pieces until golden brown, carefully turning every 10-15 minutes, depending on the size of the pieces. The chicken is done when it is no longer pink inside, its juices run clear, or your instant-read thermometer reads 165℉/75℃. You can test the chicken's doneness by piercing it with a fork.
Drain the fried chicken on paper towels and transfer it to a wire rack.