In a large bowl, combine the chicken pieces, buttermilk, and hot sauce (if using). Stir to ensure all chicken is submerged. Cover and refrigerate for at least 4 hours, or preferably overnight.

In a shallow dish or large bowl, whisk together the flour, salt, pepper, paprika, garlic powder, and onion powder. Pour oil into a large cast-iron skillet to a depth of about 1 inch. Heat over medium-high heat until it reaches 350°F (175°C) on an instant-read thermometer.

Working with one piece at a time, remove the chicken from the buttermilk, allowing excess to drip off. Dredge it thoroughly in the seasoned flour mixture, pressing to adhere. For an extra crispy crust, dip it back in the buttermilk and then back into the flour again. Place the coated chicken on a wire rack and let it rest for 15 minutes.

Carefully place 3-4 pieces of chicken into the hot oil, skin-side down. Do not overcrowd the pan. Fry for 8-12 minutes per side, turning once, until the crust is deep golden brown and the internal temperature reaches 165°F (74°C). Adjust the heat as needed to maintain an oil temperature of 325-350°F.

Remove the cooked chicken from the skillet and place it on a clean wire rack to drain. Let it rest for at least 10 minutes before serving. This helps the juices redistribute. Serve hot.