01 - Slice each chicken breast horizontally to create 4 fillets. Place between plastic wrap and pound to even thickness.
02 - Mix buttermilk, garlic powder, smoked paprika, salt, and pepper. Add chicken fillets, coat thoroughly. Marinate 15 minutes or overnight refrigerated.
03 - Combine flour and panko in shallow dish. Remove chicken from marinade, drip excess, dredge in flour mixture pressing gently to adhere.
04 - Heat 1 inch vegetable oil in deep skillet to 350°F. Fry chicken in batches 3-4 minutes per side until golden and cooked through. Drain on paper towels.
05 - Whisk mayonnaise, Parmesan, lemon juice, Dijon mustard, Worcestershire sauce, and minced garlic. Season with salt and pepper.
06 - Spread Caesar dressing on both toasted bun halves. Place chicken on bottom, top with romaine, shaved Parmesan, tomato if using. Close with top bun.
07 - Serve immediately while chicken is hot and crispy.