Cook elbow macaroni according to package instructions. 

While the pasta cools, make the dressing, place all ingredients in a medium mixing bowl. Whisk vigorously until well combined, then allow the dressing to rest on the counter. 

In a large bowl, place cooked elbow macaroni. Pour half of the dressing over the top of the al dente pasta and gently fold with a spatula or large spoon to incorporate. Add the remaining dressing and stir gently.

Sprinkle carrots, green onions, celery and yellow onion over the to the creamy mac salad. Toss gently to combine.

Cover the dish and refrigerate for at least one hour. 

Serve chilled.