In a large mixing bowl, combine the buttermilk and egg together and whisk until well combined.
In a separate bowl, mix together the flour, kosher salt, black pepper, cayenne pepper, and paprika.
Take each piece of chicken and dip it into the buttermilk mixture, making sure to coat it evenly.
Then, transfer the chicken piece to the flour mixture and coat it evenly. Repeat this process for all chicken pieces.
For the best results, allow the breaded chicken to rest in the refrigerator on a parchment-lined baking sheet for at least 2 hours before cooking.
Heat the oil in a deep fryer or a large pot to 350 degrees F. Carefully place the chicken into the hot oil, a few pieces at a time, and fry for about 10 minutes or until golden brown.
Make sure not to overcrowd the pot or fryer; otherwise, the oil temperature will drop. Once the chicken is cooked, remove it from the oil and place it on a plate lined with paper towels to remove any excess oil.
Serve your homemade Publix-style fried chicken hot with your favorite dipping sauce, and enjoy!