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, combine the mayonnaise, apple cider vinegar, Dijon mustard, sugar, salt, and black pepper. Whisk until smooth and well combined.

Add the cooled macaroni to the dressing mixture and stir until the pasta is evenly coated.

Fold in the diced celery, red bell pepper, red onion, thawed peas, and chopped parsley. If using, gently mix in the chopped hard-boiled eggs.

Cover the salad and refrigerate for at least 1 hour to allow the flavors to meld. For best results, chill for 2-3 hours.

Before serving, taste and adjust seasoning if necessary. Serve chilled.