Marinate the Chicken: In a large bowl, whisk together buttermilk, egg, 1 teaspoon salt, and ½ teaspoon black pepper. Submerge the chicken completely in the mixture. Ensure the chicken is chilled in the refrigerator for a minimum of 4 hours, though letting it sit overnight yields the best flavor.
Prepare the Coating: In another bowl, mix the flour, paprika, onion powder, garlic powder, cayenne, and the remaining salt and pepper.
Dredge the Chicken: Remove chicken from the buttermilk, letting excess drip off. Dredge each piece thoroughly in the flour mixture, shaking off the excess.
Fry the Chicken: For frying, bring the oil in a deep fryer or substantial pot up to 350°F (175°C). Fry the chicken in batches, without overcrowding the pot, for about 15 to 18 minutes, or until golden brown and an internal temperature of 165°F (74°C) is reached. Use tongs to remove the chicken and drain on paper towels.
Serve: Let the chicken rest for a few minutes before serving to maintain its crispy texture.