To make the brine; stir kosher salt into water until dissolved. Place chicken parts in a nonreactive bowl or pot; add enough brine to cover completely. Refrigerate up to 8 hours. Drain the brined chicken and rinse out the bowl it brine was in. Return the chicken to the bowl, pour milk over . Cover and refrigerate for another four hours.
Meanwhile, prepare the oil for frying by putting oil, butter in pan, I prefer a deep fryer. Cook over low heat for 30 minutes, skimming as needed, until the butter ceases to throw off foam , just before frying , increase the temperature to medium-high , began to fry, do not overcrowd the pan or the cooking oil will cool.
In another bowl mix all dry ingredients , roll chicken in dry batter, began to fry.
Using tongs, slip some of the chicken pieces, skin side down, into the heat fat until chicken is golden brown. drain on wire rack or crumpled paper towels, and serve.