01 - In a large bowl, whisk together buttermilk, hot sauce, kosher salt, and black pepper. Immerse chicken thighs in the mixture and marinate for at least 20 minutes, or refrigerate overnight for enhanced flavor and tenderness.
02 - In a shallow dish, combine all-purpose flour, cornstarch, paprika, garlic powder, onion powder, cayenne pepper, and salt. Whisk until evenly blended.
03 - Remove chicken thighs from marinade, allowing excess to drip off. Coat each thigh thoroughly in the flour mixture, pressing firmly to ensure adhesion. Arrange on a wire rack and rest for 10 minutes to set the crust.
04 - Pour vegetable oil into a heavy skillet or Dutch oven to a depth of 1 inch. Heat the oil to 350°F using a thermometer for accuracy.
05 - Fry chicken thighs in batches for 5 to 7 minutes per side, turning once, until golden brown and cooked through. The internal temperature should reach 165°F. Transfer to a wire rack to drain and rest.
06 - In a bowl, carefully whisk 1/2 cup of hot frying oil with cayenne pepper, brown sugar, chili powder, smoked paprika, garlic powder, and salt until smooth. Generously brush the sauce over both sides of each piece of fried chicken.
07 - If desired, spread unsalted butter on the cut sides of brioche buns and toast in a skillet until golden and crisp.
08 - Set a sauced fried chicken thigh on the bottom half of each bun. Top with dill pickle chips and a generous scoop of coleslaw. Cap with the upper bun and serve promptly.