01 - Whisk buttermilk, hot sauce, salt, pepper, garlic powder, and paprika in a bowl. Add chicken thighs, ensuring they are fully coated. Marinate for at least 20 minutes, up to overnight in the refrigerator for optimal flavor.
02 - Combine flour, cornflour, salt, paprika, cayenne, onion powder, and garlic powder in a large bowl. Mix thoroughly to distribute spices evenly.
03 - Remove chicken from marinade, allowing excess to drip off. Press each piece firmly into the flour mixture, ensuring a thick, even coating. Place coated pieces on a wire rack.
04 - Pour vegetable oil into a deep skillet or Dutch oven to a depth of approximately 1 inch. Heat to 350°F over medium-high heat.
05 - Fry chicken in batches for 5 to 7 minutes per side until golden brown, crispy, and cooked through to an internal temperature of 165°F. Drain on a wire rack or paper towels.
06 - Combine shredded cabbage, grated carrot, mayonnaise, vinegar, salt, and pepper in a bowl. Mix well until vegetables are evenly coated.
07 - Lightly toast buns if desired. Spread mayonnaise on bottom bun, add lettuce if using, top with fried chicken thigh, slaw, and pickle slices. Cover with top bun.
08 - Serve immediately while chicken is hot and crispy for best texture and flavor.