Place a whole cut-up chicken in a large bowl and sprinkle it with 2 teaspoons each of kosher salt, garlic powder, and onion powder.
Toss to evenly coat the chicken in the spices.
Pour in 2 cups of buttermilk and 2 tablespoons of hot sauce, stirring to combine.
Cover the bowl with plastic wrap and marinate the chicken in the fridge for at least 2 hours or overnight for best results.
In a separate medium bowl, whisk together 2 cups all-purpose flour, 1 cup cornstarch, 2 teaspoons kosher salt, 2 teaspoons paprika, and 2 teaspoons black pepper; set aside.
Preheat a deep fryer filled with peanut oil (or a neutral frying oil) to 325°F, adjusting the temperature to 300°F if the chicken browns too quickly.
If using a cast-iron skillet, monitor the heat carefully as it retains heat well.
Take each piece of chicken, let the excess buttermilk drip off, and coat thoroughly in the flour mixture, shaking off any excess.
Let the coated chicken rest for a few minutes until the coating appears slightly pasty.
Fry the chicken in batches of three or four pieces, turning every few minutes until golden brown and cooked to an internal temperature of 165°F.
Dark meat typically takes 12-14 minutes, while white meat takes 8-10 minutes; always verify with a meat thermometer.
Once fried, place the chicken on a paper towel-lined tray and sprinkle with flaked salt.
Repeat with the remaining chicken pieces and serve hot.