01 - In a large bowl, combine buttermilk, hot sauce, salt, and pepper. Add chicken thighs, ensuring each is fully coated. Marinate for at least 20 minutes or refrigerate overnight for deeper flavor.
02 - In a shallow dish, whisk together flour, cornstarch, paprika, garlic powder, onion powder, cayenne pepper, and salt until thoroughly blended.
03 - Remove chicken from marinade and allow excess to drip off. Coat each piece in the flour mixture, pressing firmly to ensure an even layer. Set on a wire rack and rest 10 minutes.
04 - Pour vegetable oil into a heavy skillet or Dutch oven to a depth of 1 inch. Heat oil to 350°F (175°C).
05 - Fry chicken thighs in batches for 5 to 7 minutes per side until golden and crisp, and an internal temperature of 165°F (74°C) is reached. Transfer to a wire rack to drain and rest.
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 generously over both sides of the fried chicken.
07 - Butter the cut sides of the brioche buns and toast in a skillet over medium heat until golden and crisp.
08 - Arrange sauced fried chicken on the bottom bun. Top with dill pickle chips and a generous scoop of coleslaw. Close with the top bun and serve immediately.