Step 1: Brine the chicken by submerging thighs in a bowl of buttermilk, seasoning with salt and pepper. Refrigerate for at least 4 hours, preferably overnight.

Step 2: In a shallow dish, combine flour, cornstarch, baking powder, cayenne, smoked paprika, brown sugar, garlic powder, and onion powder.

Step 3: Dredge marinated chicken in the flour mixture, ensuring fully coated. Let rest for 10 minutes on a wire rack.

Step 4: Heat oil in a pot to 325°F (160°C). Maintain this temperature while frying.

Step 5: Fry chicken in batches for 6-8 minutes until golden brown and cooked through.

Step 6: In a bowl, whisk together reserved hot oil, cayenne, brown sugar, and smoked paprika to create the glaze.

Step 7: Brush the hot glaze over each fried chicken piece.

Step 8: Assemble the sandwiches on toasted buns with mayonnaise or ranch and dill pickles.