Cook rotini in large pot of boiling salted water till tender but firm about 8 to 10 minutes, drain and rinse in cold water. Cover and refrigerate overnight. With the motor running, drop garlic cloves into the bowl of a food processor fitted with the steel blade. Mince, then add anchovies and process to combine. With the motor running, add oil in a thin stream until thickened.
Tear lettuce leaves into manageable pieces and place in a large salad bowl.
Add dressing and toss. Sprinkle with Parmesan cheese, toss again, and top with croutons. Serve at once, passing the pepper mill for each person to add to taste. Then pour oil over lettuce. Sprinkle pepper and salt over lettuce.