Step 1: Cook the Pasta - Bring a large pot of salted water to a rolling boil and add the cavatappi pasta. Cook according to package instructions until al dente, usually about 8-10 minutes. Once done, drain the pasta in a colander and rinse it under cold water until chilled.

Step 2: Whisk the Dressing - In a large mixing bowl, combine the mayonnaise, sour cream, white vinegar, Dijon mustard, sugar, kosher salt, and black pepper. Whisk until smooth and well-blended.

Step 3: Prepare the Pasta - Transfer cooled pasta to a large mixing bowl. Drizzle with vinegar or lemon juice to prevent sogginess.

Step 4: Combine the Dressing and Pasta - Add two-thirds of the prepared dressing to the cooled pasta and gently toss until evenly coated. Let the mixture rest for about 10-15 minutes.

Step 5: Fold in the Vegetables - Carefully fold the diced red bell pepper, celery, red onion, and carrot into the pasta mixture without overmixing.

Step 6: Adjust the Creaminess - Taste the salad and adjust with reserved dressing if needed. Check seasoning for balance.

Step 7: Refrigerate for Flavor Melting - Cover and refrigerate for at least 2-4 hours to allow flavors to meld.

Step 8: Serve and Garnish - Give a gentle stir, garnish with paprika or herbs, and serve in a shallow bowl.