01 - Boil macaroni according to package directions until al dente. Drain thoroughly and rinse under cold running water to halt cooking. Transfer to a large bowl and allow to cool completely.
02 - Whisk together mayonnaise, sour cream, Dijon mustard, apple cider vinegar, sugar, salt, black pepper, and smoked paprika in a separate mixing bowl until completely smooth and well incorporated.
03 - Add cooled macaroni, diced celery, red bell pepper, red onion, and shredded carrots to the dressing. Fold gently with a spatula until all components are evenly coated.
04 - If using, fold in sweet pickle relish and fresh chopped parsley for additional sweetness and herbal notes.
05 - Cover bowl securely with plastic wrap or lid. Refrigerate for minimum 1 hour, preferably 2-3 hours, to allow flavors to meld and develop.
06 - Stir salad once before serving. Taste and adjust seasoning with additional salt or pepper if desired. Serve cold.