01 - Slice each chicken breast in half horizontally to create 4 thin fillets for even cooking.
02 - Whisk buttermilk, garlic powder, onion powder, salt, and pepper in a bowl. Submerge chicken pieces and marinate for at least 15 minutes, up to 4 hours refrigerated for maximum flavor penetration.
03 - Arrange three shallow bowls: one with flour, one with beaten eggs, and one combining panko breadcrumbs with grated Parmesan.
04 - Remove chicken from marinade. Dredge each fillet in flour, shake off excess, dip into egg wash, then press firmly into panko-Parmesan mixture to coat completely.
05 - Heat ½ inch vegetable oil in a large skillet over medium-high heat. Fry chicken pieces 3–4 minutes per side until golden brown and internal temperature reaches 165°F. Transfer to paper towels to drain.
06 - Lightly toast brioche or sandwich buns until golden and warm.
07 - Spread Caesar dressing on both bun halves. Layer bottom bun with shredded romaine, place crispy chicken fillet on top, add additional dressing and shaved Parmesan. Finish with freshly ground black pepper and close sandwich.
08 - Serve sandwiches immediately while chicken remains hot and crispy.