01 - In a large mixing bowl, whisk together buttermilk, hot sauce, kosher salt, and black pepper. Submerge chicken thighs and refrigerate for at least 20 minutes, or up to overnight for optimal tenderness.
02 - In a shallow dish, thoroughly blend all-purpose flour, cornstarch, paprika, garlic powder, onion powder, cayenne pepper, and salt until well combined.
03 - Remove chicken from marinade, allowing excess to drip off. Dredge each thigh in the flour mixture, pressing firmly to ensure an even coating on all sides. Transfer to a wire rack and let rest for 10 minutes.
04 - Fill a heavy skillet or Dutch oven with vegetable oil to a depth of 1 inch. Heat over medium-high flame until oil registers 350°F (175°C) on a thermometer.
05 - Carefully add dredged chicken thighs to the hot oil in batches. Fry each piece for 5–7 minutes per side until deep golden brown and thoroughly crisp, ensuring internal temperature reaches 165°F (74°C). Set cooked chicken on a wire rack to drain.
06 - In a medium bowl, vigorously whisk 1/2 cup hot frying oil with cayenne pepper, brown sugar, chili powder, smoked paprika, garlic powder, and salt until homogeneous. Generously brush both sides of fried chicken with the sauce.
07 - Lightly spread the cut sides of brioche buns with unsalted butter. Toast in a skillet over medium heat until golden and crisp.
08 - Place sauced chicken thighs onto the bottom half of each toasted bun. Layer with dill pickle chips and a generous portion of coleslaw. Cap with the top bun and serve immediately.