Cook the macaroni by boiling a large pot of salted water, adding 2 cups of elbow macaroni, and cooking until al dente, about 8-10 minutes. Drain and rinse with cold water to cool.

Prepare the dressing by whisking 1 cup of mayonnaise, ¼ cup of whole milk, 2 tablespoons of brown sugar, 2 tablespoons of apple cider vinegar, and 1 tablespoon of Dijon mustard in a medium mixing bowl. Add ½ teaspoon of salt and ¼ teaspoon of black pepper.

Combine salad ingredients in a large mixing bowl: the cooled macaroni, 1 cup of grated carrot, ½ cup of finely diced yellow onion, and ½ cup of finely diced celery. Add ¼ cup of finely chopped green onions and mix gently.

Pour the prepared dressing over the salad mixture and toss gently until everything is coated. Avoid over-mixing.

Chill the salad by covering it with plastic wrap or transferring it to an airtight container for at least 30 minutes.

Serve and enjoy by giving the salad a gentle toss before serving, garnishing with extra chopped green onions if desired.