Cook the pasta in a large pot of salted boiling water for 8-10 minutes until al dente. Drain and rinse under cold water.

In a large mixing bowl, whisk together mayonnaise, sour cream, white vinegar, Dijon mustard, sugar, salt, and black pepper until smooth.

Combine the chilled pasta with two-thirds of the dressing, mixing gently to coat the pasta evenly. Let it sit for 10-15 minutes.

Fold in the diced red bell pepper, celery, red onion, and carrot, stirring gently to combine and preserve crunch.

Taste and add more dressing if needed, seasoning with additional salt and pepper as desired.

Cover and refrigerate for 2-4 hours to allow flavors to meld.

Before serving, stir gently, and garnish with paprika or fresh herbs if desired.