Bring a large pot of salted water to a boil. Add 2 cups of elbow macaroni and cook for about 8–10 minutes until al dente. Drain and rinse under cold water.

In a mixing bowl, whisk together 1 cup of mayonnaise, 2 tablespoons of Dijon mustard, 2 tablespoons of apple cider vinegar, 1 tablespoon of sugar, and a pinch of salt and black pepper.

Add the cooled macaroni to the dressing and fold gently until coated.

Fold in 1 diced red bell pepper, 1 diced celery stalk, and 1 finely chopped red onion. Mix until evenly distributed.

Incorporate optional ingredients like hard-boiled eggs, diced ham, or shredded cheddar cheese if desired.

Cover and chill for at least 1 hour before serving.