Cut the chicken breasts in half horizontally to create thinner fillets. Place them in a bowl with buttermilk and let them marinate in the fridge for at least 1 hour (or up to overnight for best flavor).
In a shallow dish, combine the breadcrumbs, grated Parmesan, garlic powder, onion powder, salt, and pepper. Mix well to ensure even distribution of the seasonings.
Remove the chicken fillets from the buttermilk, letting excess drip off. Dredge each piece in the breadcrumb mixture, pressing down firmly to ensure the breadcrumbs adhere well. Set aside on a plate.
Heat a large skillet or frying pan over medium-high heat and add enough oil to coat the bottom. Once hot, carefully place the breaded chicken fillets into the pan. Cook for about 4-5 minutes on each side, until golden brown and cooked through. (Internal temperature should reach 165°F/75°C.)
Cut the sandwich rolls in half and lightly toast them if desired. Spread a tablespoon of Caesar dressing on the bottom half of each roll. Layer on fried chicken fillets, followed by chopped romaine lettuce.
Drizzle more Caesar dressing over the lettuce and sprinkle with freshly cracked black pepper. Place the top half of the rolls on to complete the sandwiches.
Serve the Crispy Chicken Caesar Sandwiches with lemon wedges on the side for a zesty squeeze.