Corn starch has several culinary uses, such as thickening agent, binder and, in the case of fried chicken, an enhancement for breading that results in a light and flaky crust. Corn starch must be used in conjunction with all-purpose flour for optimal results – it contains too much fibrous starch to stand alone. A typical ratio uses 2 tablespoons of corn starch for every cup of all-purpose flour.
Fill a nonreactive container with a brining solution, such as 1/2 cup of kosher salt for every 2 quarts of cold water. Place the cut-up chicken pieces into the brining solution, cover and refrigerate for 10 hours.
Remove the chicken from the brine and drain off the excess. Place the chicken in a container, cover completely with whole buttermilk and refrigerate for 8 hours. Drain the chicken on a wire rack placed over a sheet pan and discard the buttermilk.
Heat the deep fryer to 350 degrees Fahrenheit. Mix the breading mixture in a large bowl; for every cup of all-purpose flour, use 2 tablespoons of cornstarch, 1/2 teaspoon of kosher salt and 1/2 teaspoon of freshly ground black pepper. Spread the seasoned flour in an even layer in a shallow dish.
Dredge the chicken pieces in the seasoned flour and shake off the excess. Fry the chicken in batches until each piece reaches a minimum internal temperature of 165 F as measured by a meat thermometer inserted in the thickest portions. Drain the oil from the chicken by placing it on a plate lined with paper towels.