Place chicken pieces in a large bowl. Pour buttermilk and hot sauce over the chicken. Mix to coat completely. Cover and refrigerate for at least 4 hours, or preferably overnight.
In a separate shallow dish, whisk together the flour, cornstarch, salt, pepper, paprika, garlic powder, cayenne pepper, thyme, and oregano. This is your dry dredge mix.
Remove chicken from the buttermilk, letting excess drip off, but do not wipe it dry.
Dredge each piece thoroughly in the dry mix, pressing the coating firmly onto the chicken.
For a thicker crust, dip the coated chicken back into the remaining buttermilk for a few seconds, then return it to the dry mix for a second, heavy dredge. Press again.
Heat 2 inches of vegetable oil in a deep, heavy-bottomed pot or Dutch oven to 325 degrees Fahrenheit. Use a thermometer to maintain this temperature.
Carefully place 3 to 4 pieces of chicken into the hot oil, ensuring you do not overcrowd the pot, which lowers the oil temperature.
Fry the chicken for 12 to 15 minutes, turning occasionally, until deep golden brown and the internal temperature reaches 165 degrees Fahrenheit. Smaller pieces cook faster.
Remove the chicken and place it on a wire rack set over a baking sheet to drain excess oil. Do not place it on paper towels, as this steams the crust.
Repeat with remaining chicken, adjusting the heat as necessary between batches to maintain 325 degrees Fahrenheit.
Notes
For extra crispy skin, let the fully dredged chicken rest on a wire rack at room temperature for 20 minutes before frying. This allows the coating to hydrate slightly.
If you prefer not to deep fry, you can bake this chicken at 400 degrees Fahrenheit for 35-45 minutes, flipping halfway, after spraying the coated pieces lightly with cooking spray.
Use a blend of half vegetable oil and half shortening for a more traditional flavor profile.