Cook the elbow macaroni according to package instructions until al dente. Drain and rinse under cold water to cool. Set aside.
In a large mixing bowl, whisk together the mayonnaise, apple cider vinegar, Dijon mustard, sugar, salt, and black pepper until smooth.
Add the cooled macaroni to the bowl with the dressing and stir to combine.
Fold in the diced celery, bell pepper, red onion, peas, and chopped hard-boiled eggs until evenly distributed.
If using, add the chopped parsley and mix gently.
Cover the salad and refrigerate for at least 1 hour before serving to allow the flavors to meld.