Cook the elbow macaroni according to package instructions until al dente.

Hard-boil the eggs by placing them in a pot and submerging them in water. Bring to a boil, then cover and let sit off the heat for 12 minutes.

While the pasta and eggs are cooking, prepare the dressing by whisking together mayonnaise, Dijon mustard, apple cider vinegar, salt, and pepper in a large bowl.

Once the macaroni is cooled, add it to the bowl with the dressing.

Peel the hard-boiled eggs and chop them into large chunks before adding them to the pasta mixture.

Add the chopped celery and red onion to the pasta mixture, stirring until everything is well combined.

Taste and adjust seasoning as necessary, adding more salt, pepper, or vinegar as needed.

Chill the macaroni salad in the refrigerator for at least 30 minutes before serving.