Place the lettuce in a large bowl. Add dressing, as much as desired, and toss until the leaves are lightly coated. I recommend starting with a little dressing, tossing, and then tasting. You might not need it all.
Add the croutons (however many you want) and Parmesan cheese and toss again. Serve immediately.
You can use 1 large head Romaine lettuce, discard outer wilted leaves. The dressing and croutons can be made in advance.