Season and grill chicken until cooked through (165°F internal temperature).
Let chicken rest for 5 minutes, then slice thinly.
In a bowl, whisk together all Caesar dressing ingredients until creamy and smooth.
Toast the bread slices until golden and crisp.
Spread a generous layer of Caesar dressing on the toasted bread.
Layer romaine lettuce, sliced chicken, and shaved Parmesan.
Add croutons (and bacon if desired) for extra crunch.
Top with another bread slice, slice diagonally, and serve.