01 - In a large mixing bowl, combine buttermilk, hot sauce, kosher salt, and black pepper. Add chicken thighs, ensuring they are fully coated. Cover and marinate for at least 20 minutes or refrigerate overnight.
02 - In a shallow dish, whisk together flour, cornstarch, paprika, garlic powder, onion powder, cayenne pepper, and salt until evenly blended.
03 - Remove chicken from marinade, allowing any excess to drip off. Dredge each thigh thoroughly in the flour mixture, pressing to ensure an even coating. Arrange coated chicken on a wire rack and let rest for 10 minutes.
04 - Pour vegetable oil into a heavy skillet or Dutch oven to achieve a 1-inch depth. Heat the oil over medium-high heat to 350°F (175°C).
05 - Working in batches to avoid crowding, fry the dredged chicken thighs for 5 to 7 minutes on each side, or until golden and crisp. Confirm internal temperature reaches 165°F (74°C). Transfer to a clean wire rack to drain.
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. Gently brush the hot sauce on both sides of each fried chicken thigh.
07 - Spread unsalted butter on the cut sides of each brioche bun. Place buns cut side down in a skillet over medium heat and toast until golden brown.
08 - Place each sauced chicken thigh on the bottom half of a bun. Top with dill pickle chips and a generous portion of coleslaw. Cap with the top bun and serve immediately for optimal texture and flavor.