01 - Whisk together buttermilk, hot sauce, garlic powder, onion powder, salt, and pepper in a large bowl. Submerge chicken thighs completely, cover, and refrigerate for minimum 2 hours or overnight for optimal flavor penetration.
02 - Combine flour, cornstarch, paprika, baking powder, cayenne pepper, salt, and black pepper in a shallow dish. Mix thoroughly to ensure even distribution of spices and leavening agents.
03 - Pour vegetable oil into deep fryer or heavy-bottomed pot. Heat to 350°F, maintaining consistent temperature throughout cooking process for optimal crisping.
04 - Remove chicken from marinade, allowing excess liquid to drip off. Press each piece firmly into flour mixture, turning to coat completely and creating textured, craggy surface for maximum crunch.
05 - Carefully lower coated chicken into hot oil using tongs. Fry 6 to 8 minutes per piece, turning once halfway through, until deep golden brown and internal temperature reaches 165°F. Transfer to wire rack to drain.
06 - Lightly toast cut sides of buns in pan or toaster until golden brown and warmed through, creating sturdy base for toppings.
07 - Combine mayonnaise with hot sauce in small bowl, adjusting ratio to preferred heat level. Whisk until smooth and fully incorporated.
08 - Spread spicy mayo on bottom bun. Layer lettuce leaf, crispy fried chicken thigh, tomato slice, and pickle chips. Crown with top bun and serve immediately while chicken remains hot and crispy.