In a medium-sized bowl, whisk together mayonnaise, sour cream, Dijon mustard, and apple cider vinegar. Season with salt and pepper to taste. Set aside.

Bring salted water to a boil. Add pasta and cook until al dente, about 8-10 minutes. Drain and rinse under cold water.

In a large mixing bowl, combine the cooled cooked pasta, cubed chicken, crumbled bacon, halved cherry tomatoes, and sliced red onion. Toss gently.

Pour the dressing over the salad mixture and toss gently until well coated. Avoid overmixing.

Just before serving, fold in the cubed toasted bread or croutons.

Spoon into servings bowls and garnish with fresh herbs if desired. Serve chilled or at room temperature.