01 - Slice each chicken breast horizontally to create 4 thin, even fillets for uniform cooking.
02 - Whisk buttermilk, garlic powder, onion powder, salt, and pepper in a bowl. Submerge chicken pieces and marinate for 15 minutes, or refrigerate up to 4 hours for enhanced flavor.
03 - Arrange three shallow bowls: first with flour, second with beaten eggs, third with panko breadcrumbs mixed with grated Parmesan.
04 - Remove chicken from marinade, allowing excess to drip off. Dredge each piece in flour, dip into egg wash, then press firmly into panko-Parmesan mixture to coat completely.
05 - Heat ½ inch vegetable oil in large skillet over medium-high heat. Fry chicken 3–4 minutes per side until golden brown and internal temperature reaches 165°F. Transfer to paper towels to drain.
06 - Lightly toast buns until golden for texture and to prevent sogginess.
07 - Spread Caesar dressing on bottom buns. Layer with shredded romaine, crispy chicken fillet, additional dressing, shaved Parmesan, and fresh black pepper. Close with top buns and serve immediately.