1) To marinate the chicken: Combine the buttermilk and seasonings in a bowl large enough to hold all the chicken pieces you want to fry. Remove the skin (it'll save you a significant amount of fat) and submerge in the buttermilk mixture. Cover and refrigerate for at least 4 hours, or overnight.
2) To make the seasoned flour: Whisk together the flours and seasonings in a large bowl; set aside until needed.
3) To dredge and fry: Preheat the oven to 350°F. Place a rack on a baking sheet and place it in the oven. Whisk together the flours and seasonings. Put a deep cast-iron pan on the stove and heat 1 1/2" of peanut or canola oil in it over medium heat, until the oil reaches 350°F.
4) Take the pieces of chicken out of the soak, one by one, and let the extra liquid run off. Put the chicken in the flour dredge and coat thoroughly. Place gently into the oil and fry for 5 to 7 minutes, until golden brown, then turn and fry for another 5 minutes.
5) Drain the chicken briefly on absorbent paper, then place on the rack in the oven while you finish frying the rest of the meat. The last pieces will need about 15 minutes of oven time to make sure they're cooked all the way through. Yield: 8 pieces of chicken from one bird; (2 wings, 2 thighs, 2 drumsticks, 2 breasts).