Step 1

Whisk together mayonnaise, buttermilk, sour cream, garlic powder, onion powder, Worcestershire sauce, pepper, 2 tablespoons of the parsley, 2 tablespoons of the chives, and 3/4 teaspoon of the salt in a medium bowl. Refrigerate ranch dressing until ready to use.

Step 2

Prepare pasta according to package directions. Toss together cooked pasta, bacon, romaine, tomatoes, Cheddar, shallot, and remaining 2 tablespoons parsley, 2 tablespoons chives, and 3/4 teaspoon salt in a large bowl. Pour ranch dressing over pasta mixture, and toss to coat. Serve immediately.