01 - Combine buttermilk, hot sauce, kosher salt, and black pepper in a large mixing bowl. Submerge chicken thighs and marinate for at least 20 minutes or up to overnight in the refrigerator.
02 - In a shallow dish, thoroughly mix all-purpose flour, cornstarch, paprika, garlic powder, onion powder, cayenne pepper, and salt.
03 - Remove chicken from marinade, allowing excess to drip off. Evenly coat each thigh in the flour mixture, pressing to adhere. Set aside on a wire rack for 10 minutes.
04 - Pour vegetable oil into a heavy skillet or Dutch oven to a depth of 1 inch. Heat oil to 350°F.
05 - Fry chicken thighs in batches for 5 to 7 minutes per side, or until golden brown, crisp, and internal temperature reaches 165°F. Transfer cooked pieces to a wire rack.
06 - In a medium bowl, combine 1/2 cup hot frying oil with cayenne pepper, brown sugar, chili powder, smoked paprika, garlic powder, and salt. Whisk until smooth and brush generous amounts over both sides of fried chicken.
07 - If desired, butter the cut sides of the brioche buns and toast them in a skillet until golden.
08 - Place sauced chicken on bottom half of each bun. Top with dill pickle chips and a generous scoop of coleslaw. Add top bun and serve immediately.