To prepare a buttermilk brine, combine 1 quart of buttermilk, 4 teaspoons of salt and 1 teaspoon of black pepper in a large resealable plastic bag. To use it for fried chicken, add the meat to the mixture, and wait for a minimum of 4 hours. Remove the chicken from the brine and let it rest so that salt can distribute evenly throughout the meat. Drain the chicken completely of the remaining brine.
Combine flour, 1/4 teaspoon of salt and 1/4 teaspoon of black pepper in a large bowl. Dip the chicken pieces into the mixture, ensuring each piece is coated uniformly. In a Dutch oven, pour cooking oil until it reaches a depth of approximately 2 inches. Heat the oil to 375 degrees Fahrenheit.
Divide the chicken into two batches. Starting by carefully inserting the larger pieces into the oil. Wait for approximately 10 minutes and check whether the pieces are golden-brown and crispy. If they are, drain them with paper towels and keep them in an oven to stay warm as you fry the rest of the pieces. If the chicken pieces achieve the golden-brown color but aren't well-fried inside, heat them in the oven at a temperature of 400 degrees Fahrenheit.