Begin by bringing a large pot of salted water to a rolling boil over high heat. Once boiling, add the elbow pasta and cook for 8 to 10 minutes or until al dente, stirring occasionally. Drain the pasta in a colander and let it sit to cool slightly.

In a mixing bowl, combine mayonnaise, sour cream, red wine vinegar, sugar, yellow mustard, salt, and pepper. Whisk together until smooth.

Rinse the cooked pasta under cold running water in the colander to stop cooking. Shake off excess water.

In a large mixing bowl, add the cooled pasta and pour the creamy dressing over it. Toss to coat. Fold in diced celery, red bell pepper, and red onion.

Cover the bowl with plastic wrap or a lid and refrigerate the salad for at least 2 hours, or overnight for best results.

Before serving, give the salad a quick stir. If it's dry, drizzle a little mayo or milk to reach desired creaminess.