Cook macaroni noodles according to package instructions. Drain, rinse under cold water, and add the noodles to a large bowl.

To the cooled macaroni, add the chopped carrots, celery, and onion.

In a small mixing bowl, add the dairy-free mayo, apple cider vinegar, sweet relish, mustard, sugar, salt and pepper.

Mix the dressing well to combine, and pour it over the macaroni and vegetables. Stir well to combine the dressing, making sure it coats all of the macaroni and vegetables.

Taste, and adjust seasoning as needed, adding more salt or pepper if desired. Stir in the fresh parsley and chill before serving.