Cook macaroni in a large pot of salted boiling water for 7-8 minutes until al dente. Drain and rinse under cold water.

In a large mixing bowl, combine mayonnaise, sour cream, apple cider vinegar, and Dijon mustard. Whisk until smooth.

Fold in sugar, salt, and pepper to the dressing. Taste and adjust seasoning as needed.

Add the cooled macaroni to the dressing, then gently fold in diced red onion, celery, red bell pepper, and parsley.

Cover or transfer to an airtight container and refrigerate for at least 1 hour before serving.