01 - Slice each chicken breast in half horizontally to create 4 thin fillets.
02 - In a bowl, whisk buttermilk, garlic powder, onion powder, salt, and pepper. Add chicken and marinate for at least 15 minutes (up to 4 hours in the refrigerator for best flavor).
03 - Prepare three bowls: one with flour, one with beaten eggs, and one with panko mixed with grated Parmesan.
04 - Remove chicken from marinade. Dredge each piece in flour, dip in egg, then coat thoroughly in the panko-Parmesan mixture.
05 - Heat ½ inch of vegetable oil in a large skillet over medium-high heat. Fry chicken pieces for 3–4 minutes per side until golden brown and cooked through (internal temperature 165°F). Drain on paper towels.
06 - Toast buns lightly.
07 - Spread Caesar dressing inside each bun. Layer with lettuce, a crispy chicken fillet, more Caesar dressing, and shaved Parmesan. Top with black pepper.
08 - Close sandwiches and serve immediately.