In a large pot, bring salted water to a rolling boil. Add 1 lb of elbow macaroni and cook for 7-8 minutes until al dente. Drain and rinse under cold water to cool.

In a mixing bowl, whisk together 1 cup of mayonnaise, ¼ cup of sour cream, 2 tablespoons of apple cider vinegar, 1 tablespoon of Dijon mustard, 1 teaspoon of sugar, ½ teaspoon of salt, and ½ teaspoon of black pepper until smooth.

Transfer the cooled macaroni to the bowl with the dressing. Add ½ cup each of diced red onion, diced celery, and diced red bell pepper. Fold gently to combine.

Cover tightly and refrigerate for at least 1 hour, preferably 2 hours, to allow flavors to meld.

After chilling, stir gently to combine. Taste and adjust seasoning if needed. Serve cold.