Whisk together the buttermilk, paprika, cayenne, and salt in a large bowl.
Add the chicken pieces to the bowl, mixing to coat them with the marinade.
Cover the bowl, and let the chicken sit in the refrigerator for at least 4 hours or overnight.
Remove the chicken pieces from the buttermilk, and pat dry with paper towels.
Use a basting brush to coat the chicken pieces with a thin layer of yellow mustard.
Mix the flour, seasoned salt, garlic powder, and onion powder in a gallon-size resealable bag, shaking to combine.
Add 2 pieces of the chicken at a time to the bag, and shake to coat. Repeat with the remaining chicken pieces.
Heat the oil to 375 F in a large pot, Dutch oven, or fryer.
Carefully lower the chicken a few pieces at a time into the hot oil.
Cover, and fry the chicken until deep golden brown, about 8 to 10 minutes.
Turn the pieces over, and cook for an additional 6 to 8 minutes, or until the chicken reaches an internal temperature of 160 F for wings and breasts and 175 F for drumsticks and thighs.