In a large bowl, combine buttermilk, garlic powder, onion powder, paprika, salt, and black pepper. Add chicken breasts, ensuring they are fully submerged. Cover and refrigerate for at least 1 hour or up to overnight for best results.
Preheat your oven to 400°F. Line a baking sheet with parchment paper.
In a shallow dish, mix together flour, panko breadcrumbs, and grated Parmesan cheese. Remove chicken from the marinade, allowing excess to drip off, then dredge each piece in the breadcrumb mixture, pressing gently to adhere.
Place the breaded chicken on the prepared baking sheet. Bake for 20-25 minutes, or until the chicken is golden brown and cooked through (internal temperature should reach 165°F).
While the chicken is baking, prepare the sauce by whisking together mayonnaise, lemon juice, and Worcestershire sauce in a small bowl.
Once the chicken is done, let it rest for a few minutes. Slice the sandwich rolls in half and lightly toast them if desired.
To assemble, spread the sauce on both halves of the rolls. Layer with chopped romaine lettuce, a crispy chicken breast, and drizzle with Caesar dressing. Top with extra Parmesan cheese if desired.
Close the sandwiches and serve immediately.