01 - In a bowl, whisk together buttermilk, garlic powder, onion powder, salt, and black pepper. Submerge chicken fillets, cover, and refrigerate at least 15 minutes or up to 4 hours for optimal tenderness.
02 - Combine all-purpose flour, panko breadcrumbs, and grated Parmesan in a shallow dish. In a separate bowl, beat eggs until well mixed.
03 - Remove marinated chicken from buttermilk. Dredge each fillet in the flour mixture, then dip in beaten eggs, followed by another layer of the flour mixture for maximum crispiness.
04 - Heat about 1/2 inch of vegetable oil in a skillet over medium-high to 350°F. Fry chicken fillets for 3 to 4 minutes per side, until golden brown and thoroughly cooked. Drain on paper towels.
05 - Toss shredded romaine lettuce with Caesar dressing in a mixing bowl. Add shaved Parmesan and combine gently.
06 - Spread unsalted butter on the cut sides of each bun if desired. Toast buns on a skillet or under the broiler until golden. Place one fried chicken fillet on the bottom half of each bun. Add prepared Caesar salad and top with bun lids.
07 - Serve each sandwich immediately, optionally accompanied by extra Caesar dressing or lemon wedges on the side.