In a medium bowl, whisk together the Dijon mustard, lemon juice, Worcestershire sauce, anchovy paste, minced garlic, and mayonnaise. Season with black pepper and blend until smooth. Set aside.

Bring a large pot of salted water to a boil. Add the pasta and cook for about 10 minutes until al dente. Drain and rinse with cold water.

Dice cooked chicken into 1-inch chunks and chop romaine lettuce into bite-sized pieces. Wash lettuce thoroughly before chopping.

In a large mixing bowl, combine cooled pasta, diced chicken, and chopped romaine. Drizzle the Caesar dressing over the mixture and toss gently until well coated.

Just before serving, add croutons and extra Parmesan cheese. Serve immediately or refrigerate leftovers for up to 3 days.