01 - Whisk together buttermilk, hot sauce, salt, black pepper, garlic powder, and paprika in a large bowl until thoroughly combined. Add chicken thighs and turn to coat completely. Cover and marinate for at least 20 minutes, or refrigerate overnight for maximum flavor penetration.
02 - Combine flour, cornstarch, salt, paprika, cayenne pepper, onion powder, and garlic powder in a wide shallow bowl. Whisk vigorously to evenly distribute spices throughout the flour mixture.
03 - Remove chicken from marinade, allowing excess liquid to drip off. Press each thigh firmly into the flour mixture, ensuring complete coverage on all sides. Shake gently to remove loose flour and transfer to a wire rack. Let rest for 5 minutes to help coating adhere.
04 - Pour vegetable oil into a deep skillet or Dutch oven to a depth of 1 inch. Heat over medium-high heat until oil reaches 350°F. Maintain this temperature throughout frying for optimal crisping.
05 - Carefully place 2 chicken thighs in the hot oil without crowding the pan. Fry for 5 to 7 minutes per side until deep golden brown and crispy. Verify doneness with an instant-read thermometer inserted into the thickest part reaching 165°F. Transfer to a clean wire rack to drain. Repeat with remaining chicken.
06 - Toss shredded cabbage and grated carrot in a medium bowl. Add mayonnaise and apple cider vinegar, mixing until evenly coated. Season with salt and pepper to taste. Refrigerate until ready to assemble.
07 - Split burger buns in half and place cut-side up in a dry skillet over medium heat. Toast for 1 to 2 minutes until lightly golden and warmed through.
08 - Spread mayonnaise on the bottom bun if using. Layer lettuce, a fried chicken thigh, a generous portion of slaw, and pickle slices. Top with the remaining bun half. Serve immediately while chicken is hot and crispy.