Cook the Pasta: Boil elbow macaroni according to package instructions until al dente. Drain and rinse with cold water to cool it quickly.
Make the Dressing: In a large bowl, mix together mayonnaise, mustard, apple cider vinegar, sugar, salt, and pepper until smooth.
Chop Veggies: While the pasta cools, dice bell pepper, celery, red onion, and pickles.
Combine Everything: Add cooled macaroni to the dressing, then fold in the chopped veggies and eggs (if using). Stir well to coat everything evenly.
Chill: Cover and refrigerate for at least 1 hour to let the flavors meld together.
Serve: Garnish with chopped parsley and serve cold.