First, heat up a large pot of salted water till it boils. Add the elbow macaroni and simmer for the amount of time specified on the package, usually 8 to 10 minutes, or until al dente. To stop the macaroni from cooking, drain and rinse with cold water. Set aside.

In a large mixing bowl, whisk together the mayonnaise, milk, apple cider vinegar, and sugar until well combined. This dressing should be creamy with a slight tang from the vinegar and a hint of sweetness from the sugar.

Stir the macaroni into the dressing after it has cooled. Stir until the macaroni is well coated.

Next, gently fold in the chopped eggs, shredded carrot, chopped celery, and finely chopped onion. Mix until all of the ingredients are incorporated equally.

To taste, add more salt and pepper to the salad. Be careful not to overdo it, as the flavors will meld together as the salad chills.

Cover the bowl with plastic wrap or transfer the salad to an airtight container and refrigerate for at least 2 hours, preferably overnight, to allow the flavors to develop.