In a small bowl, whisk together mayonnaise, sour cream, Dijon mustard, and apple cider vinegar. Season with salt and pepper. Set aside.

In a large mixing bowl, combine cooked rotini pasta, diced chicken, and crumbled bacon. Add cherry tomatoes, red onion, and romaine lettuce. Toss gently until mixed.

Pour the dressing over the salad and toss to coat well.

Just before serving, fold in toasted bread cubes or croutons.

Garnish with fresh herbs and serve chilled or at room temperature.