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 refrigerate overnight for enhanced flavor.
02 - In a shallow dish, whisk together all-purpose flour, cornstarch, paprika, garlic powder, onion powder, cayenne pepper, and salt until fully blended.
03 - Remove chicken thighs from marinade, allowing any excess to drip off. Dredge thoroughly in the flour mixture, pressing to ensure an even coating. Place coated pieces on a wire rack and let rest for 10 minutes.
04 - Pour vegetable oil into a heavy skillet or Dutch oven to a depth of 1 inch. Heat over medium-high until oil reaches 350°F.
05 - Working in batches, fry chicken thighs for 5 to 7 minutes per side, or until deep golden and crispy. Ensure internal temperature reaches 165°F. Transfer to a 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. Generously brush sauce onto both sides of each fried chicken thigh.
07 - If desired, spread the cut sides of brioche buns with unsalted butter. Toast in a skillet over medium heat until golden brown.
08 - Arrange a sauced chicken thigh on the base of each bun. Top with dill pickle chips and a generous scoop of coleslaw. Finish with the top bun and serve immediately.