Bring a large pot of water to a rolling boil, adding a pinch of salt. Cook the elbow macaroni for 7-8 minutes until al dente. Drain and rinse under cold water, then air dry on a baking sheet.

In a mixing bowl, whisk together the mayonnaise, sour cream, apple cider vinegar, Dijon mustard, sugar, salt, and black pepper until smooth and creamy. Adjust seasoning as necessary.

Add the cooled macaroni to the dressing, ensuring it's completely cooled. Fold in the diced red onion, celery, and red bell pepper, then sprinkle with chopped parsley and toss gently.

Cover the bowl with plastic wrap and refrigerate for at least 1 hour, ideally 2 hours, to allow flavors to meld.

Before serving, stir the salad gently and transfer it to a serving dish, garnishing with extra parsley. Enjoy chilled.