01 - Whisk buttermilk, hot sauce, salt, pepper, garlic powder, and paprika in a bowl. Submerge chicken thighs completely in the marinade. Refrigerate for at least 20 minutes or overnight for optimal flavor penetration.
02 - Combine flour, cornstarch, salt, paprika, cayenne pepper, onion powder, and garlic powder in a large bowl. Mix thoroughly to distribute spices evenly.
03 - Remove chicken from marinade, allowing excess liquid to drip off. Press each piece firmly into the flour mixture to create a thick, even coating. Shake off excess and arrange on a wire rack.
04 - Pour vegetable oil to a depth of 1 inch in a deep skillet or Dutch oven. Heat to 350°F, maintaining temperature throughout frying.
05 - Fry chicken in batches, cooking 5-7 minutes per side until golden brown and crispy. Verify internal temperature reaches 165°F. Transfer to wire rack or paper towels to drain.
06 - Toss shredded cabbage and grated carrot with mayonnaise and apple cider vinegar. Season with salt and pepper to taste. Mix until vegetables are evenly coated.
07 - Lightly toast burger buns if desired. Spread mayonnaise on bottom bun, layer with lettuce, fried chicken, slaw, and pickle slices. Top with remaining bun half.
08 - Serve immediately while chicken remains hot and crispy for best texture and flavor.