This scrumptious and healthy salad combines elements of Caesar salad, pasta salad and chicken salad for an easy weeknight dinner that comes together in less than 30 minutes (and most of the prep can be done ahead). Use your blender to whip together the tangy buttermilk-based dressing, which would also be great on a salmon or chickpea salad.
Combine buttermilk, yogurt, oil, lemon juice, mustard, anchovy paste, garlic, 1/2 cup Parmesan and 1/4 teaspoon each salt and pepper in a blender; puree on high speed until smooth, about 1 minute. Set aside.
Cook pasta according to package directions, omitting salt. Drain, reserving 1 cup cooking water.
Combine the pasta, chicken, tomatoes, 1/4 cup of the reserved cooking water and the remaining 1/4 teaspoon each salt and pepper in a large bowl. Stir in the buttermilk dressing until thoroughly combined. Stir in additional cooking water as needed for a creamy consistency. Cover and chill for at least 30 minutes or up to 2 days.
Just before serving, stir in lettuce; sprinkle with the remaining 1/4 cup Parmesan.