01 - In a large mixing bowl, whisk together buttermilk, hot sauce, kosher salt, and black pepper. Submerge the chicken thighs, ensuring all pieces are coated. Cover and marinate for at least 20 minutes, ideally overnight in the refrigerator.
02 - In a shallow dish, stir together the all-purpose flour, cornstarch, paprika, garlic powder, onion powder, cayenne pepper, and salt until fully blended.
03 - Remove chicken from marinade, letting excess liquid drip away. Press each thigh into the flour mixture, coating thoroughly and pressing to adhere. Place coated chicken on a wire rack and allow to rest for 10 minutes.
04 - Pour vegetable oil into a heavy skillet or Dutch oven to a depth of 1 inch. Place over medium-high heat and bring to 350°F (175°C).
05 - Using tongs, carefully add chicken thighs to hot oil in batches. Fry for 5 to 7 minutes per side until golden brown, crispy, and internal temperature reaches 165°F (74°C). Transfer fried chicken to a wire rack to drain.
06 - In a medium bowl, carefully whisk together 1/2 cup of the hot frying oil with cayenne pepper, brown sugar, chili powder, smoked paprika, garlic powder, and salt until smooth. Using a pastry brush, generously coat both sides of the fried chicken with the sauce.
07 - If desired, butter the cut sides of brioche buns. Toast on a skillet over medium heat until golden and crisp.
08 - Arrange sauced chicken on each bun bottom. Top with dill pickle chips and a generous scoop of coleslaw. Cap with the top bun and serve immediately.