Prepare the dressing by whisking together mayonnaise, sour cream, Dijon mustard, apple cider vinegar, salt, and black pepper until smooth. Set aside.

In a large mixing bowl, add cooked pasta, chopped chicken, crumbled bacon, halved cherry tomatoes, red onion, and romaine lettuce. Toss gently.

Drizzle the prepared dressing over the salad mixture and gently toss until well-coated.

Before serving, fold in the toasted bread cubes or croutons for crunch.

Garnish with fresh parsley or chives and serve immediately or chill for 30 minutes.