Cook the elbow macaroni according to package instructions until al dente. Drain and rinse under cold water to cool.

In a large mixing bowl, combine the mayonnaise, apple cider vinegar, Dijon mustard, sugar, salt, and black pepper. Whisk until smooth.

Add the cooled macaroni to the bowl with the dressing and stir to coat.

Fold in the diced celery, red bell pepper, red onion, peas, and chopped hard-boiled eggs, if using. Mix until all ingredients are well combined.

Cover the salad and refrigerate for at least 1 hour to allow the flavors to meld.

Before serving, give the salad a good stir and garnish with fresh parsley if desired.