Cook the macaroni according to the package instructions until it is al dente. Make sure to add salt to the boiling water for flavor. Drain the cooked macaroni and rinse it under cold water to cool it down. Set it aside to drain completely.

In a large mixing bowl, add the grated carrot, minced onion, diced celery (if using), and chopped parsley (if using). Add the cooked and cooled macaroni to the bowl.

In a large bowl, whisk together the mayonnaise, apple cider vinegar, milk, sugar, salt, and black pepper until well combined. This will be the creamy sauce.

Add to the cooked pasta mixture and mix everything together until the vegetables are evenly distributed throughout the salad.

Cover the bowl with plastic wrap and refrigerate for at least 2 hours or overnight. This will allow the flavors to meld together and the salad to chill.

Before serving, give the macaroni salad a good stir. Taste and adjust the seasoning if needed by adding more salt, pepper, or sugar.

Serve the Hawaiian macaroni salad chilled as a perfect side dish with your favorite main courses, such as grilled meats or seafood. Enjoy!