In a large bowl, whisk together the buttermilk, salt, and black pepper. Add the chicken pieces to the bowl, ensuring they are fully submerged. Cover the bowl and refrigerate for at least 2 hours, or preferably overnight.

In a shallow dish or a large resealable bag, combine the all-purpose flour, salt, paprika, garlic powder, onion powder, and cayenne pepper (if using). Mix well to ensure all spices are evenly distributed.

Remove the chicken from the buttermilk brine, letting any excess drip off. Dredge each chicken piece in the seasoned flour mixture, pressing to ensure it is thoroughly coated. Shake off any excess flour.

Heat the vegetable oil in a large, heavy-bottomed skillet or Dutch oven over medium-high heat to about 350°F (175°C).

Carefully place the coated chicken pieces into the hot oil, being careful not to overcrowd the pan. Fry in batches if necessary.

Fry the chicken for about 6-8 minutes per side, or until golden brown and cooked through. The internal temperature should reach 165°F (74°C).

Remove the fried chicken from the oil and place it on a wire rack set over a baking sheet to drain any excess oil. This helps keep the chicken crispy.

Serve the fried chicken hot with your favorite sides.