Refrigerate the chicken in the buttermilk and hot sauce for 4 hours, then let it drain for 5 minutes.
Heat the oil in a deep heavy pot to 325°F and mix the flour, paprika, cayenne, garlic powder and salt.
Press each thigh into the flour mixture, mist the surface with a spoonful of marinade, and dredge again to build craggy patches.
Fry 2 pieces at a time for 12 to 15 minutes, turning twice, until deeply browned and 165°F at the thickest part without touching bone.
Rest the chicken on a rack for 8 minutes so the crust sets instead of steaming on paper towels.