Whisk together the buttermilk and hot sauce in a large bowl. Submerge the chicken pieces in the buttermilk mixture and refrigerate overnight.
Take the chicken out of the fridge, remove it from the buttermilk and drain on a rack set over a baking sheet to catch any excess brine. Set aside. Whisk the flour together with the panko, salt and pepper. One by one, dredge the chicken pieces in the flour mixture, tapping off excess breading. Set the breaded chicken back on the rack and set aside.
Preheat the oven to 350 degrees F.
Pour enough peanut oil into a Dutch oven so that there is 2 inches of oil but it does not go higher than halfway up the pot. Heat over medium-high heat until the oil registers 350 degrees F on a thermometer.
Fry the chicken in batches of 3 or 4 pieces, turning every 1 to 2 minutes, and watching the oil temperature closely. The chicken should be cooked to a deep golden brown and an internal temperature of 165 degrees F, about 10 minutes for wings and 12 minutes for breasts, thighs and legs. After taking the chicken out of the oil, set it on a baking sheet, immediately sprinkle with salt, and then place it in the oven for 5 minutes to finish cooking through. When done, place the fried chicken on a clean rack with layered paper towels on the bottom to absorb grease. Let cool for about 10 minutes before serving.