Bring a large pot of salted water to a rolling boil. Add elbow macaroni and cook for 8–10 minutes, or until al dente. Drain and rinse under cold water.

In a large bowl, whisk together mayonnaise, Dijon mustard, apple cider vinegar, sugar, salt, and black pepper until smooth.

Add cooled macaroni to the bowl with the dressing and gently toss until coated.

Fold in diced red bell pepper, celery, red onion, parsley, and sweet pickles. Mix gently.

Add any optional ingredients like hard-boiled eggs, diced ham, or shredded cheese.

Cover with plastic wrap and refrigerate for at least 1 hour before serving.