01 - In a large mixing bowl, blend buttermilk, hot sauce, kosher salt, and ground black pepper. Submerge chicken thighs fully and marinate for at least 20 minutes or up to overnight in the refrigerator.
02 - In a shallow dish, combine all-purpose flour, cornstarch, paprika, garlic powder, onion powder, cayenne pepper, and salt until evenly incorporated.
03 - Remove chicken from the marinade, allowing excess liquid to drain. Thoroughly coat each thigh in the flour mixture, pressing firmly to adhere. Rest pieces on a wire rack for 10 minutes.
04 - Fill a heavy skillet or Dutch oven with vegetable oil to a depth of 1 inch. Heat oil to 350°F.
05 - Fry chicken thighs in batches, 5–7 minutes per side, until deeply golden and crisp. Ensure internal temperature reaches 165°F. Allow excess oil to drain on a wire rack.
06 - In a medium bowl, combine 1/2 cup hot frying oil, cayenne pepper, brown sugar, chili powder, smoked paprika, garlic powder, and salt. Whisk until smooth, then brush liberally on both sides of fried chicken.
07 - Brush cut sides of brioche buns with unsalted butter and toast in a skillet until golden brown.
08 - Place sauced chicken thighs on the bottom half of each bun. Top with dill pickle chips and a generous portion of coleslaw. Set the top bun in place and serve immediately.