01 - In a mixing bowl, combine buttermilk, garlic powder, onion powder, salt, and pepper. Submerge chicken fillets, cover, and refrigerate for at least 15 minutes or up to 4 hours for enhanced tenderness.
02 - Mix flour, panko breadcrumbs, and grated Parmesan in a shallow dish. In a separate bowl, beat the eggs until well blended.
03 - Remove chicken from marinade. Dredge each fillet in the flour mixture, then coat with beaten egg, and return to the flour mixture for a double layer of crispiness.
04 - In a skillet, heat 1/2 inch of vegetable oil to 350°F. Fry chicken fillets for 3–4 minutes per side until golden brown and cooked through. Transfer to paper towels to drain excess oil.
05 - Toss shredded romaine lettuce with Caesar dressing in a bowl. Add shaved Parmesan and gently mix to combine.
06 - Spread unsalted butter on the cut sides of buns. Toast in a skillet or under a broiler until golden brown.
07 - Place a fried chicken fillet on each bottom bun. Spoon Caesar salad over chicken. Cap with the top bun and serve immediately.