Cook the pasta. Bring a large pot of salted water to a boil. Cook pasta until just al dente.
Drain and rinse briefly under cool water to stop the cooking. Toss with a splash of olive oil so it doesn’t stick.
Prep the chicken. If using leftover or rotisserie chicken, shred or chop it into bite-size pieces. If cooking fresh, season with salt and pepper and grill or pan-sear until cooked through, then slice.
Make the dressing. In a bowl, whisk together mayonnaise, yogurt (if using), lemon juice and zest, garlic, Dijon, Worcestershire, and anchovy paste.
Stream in olive oil while whisking until smooth. Stir in Parmesan. Season with salt and plenty of black pepper.
The dressing should be creamy but pourable; thin with a splash of water if needed.
Prep the greens. Chop romaine into bite-size pieces. Rinse and dry thoroughly. Dry lettuce is key for a crisp salad that doesn’t get soggy.
Toss the base. In a large bowl, combine cooled pasta and chicken. Add half the dressing and toss until lightly coated.
Add the crunch. Fold in romaine and most of the croutons.
Drizzle in more dressing until everything is well coated but not heavy. Taste and adjust seasoning with salt, pepper, or more lemon.
Finish and serve. Top with extra Parmesan, fresh cracked pepper, and remaining croutons. Serve right away for best texture.