Step 1: Cook the Macaroni: Bring a large pot of salted water to a boil. Add the elbow macaroni and cook according to package directions until al dente. This typically takes about 7-8 minutes. Avoid overcooking the macaroni, as it will become mushy.
Step 2: Drain and Rinse: Once the macaroni is cooked, drain it immediately and rinse it thoroughly with cold water. This stops the cooking process and removes excess starch, which helps prevent the salad from becoming sticky. Ensure all the water is drained.
Step 3: Prepare the Dressing: In a large bowl, whisk together the mayonnaise, white vinegar, sugar, milk, salt, and pepper until smooth and well combined. The dressing should have a slightly tangy and sweet flavor. Adjust the sugar or vinegar to taste.
Step 4: Combine Ingredients: Add the drained macaroni, diced celery, and diced yellow onion to the bowl with the dressing. Gently fold all the ingredients together until the macaroni is evenly coated with the dressing. Avoid overmixing, as this can cause the macaroni to break apart.
Step 5: Chill and Serve: Cover the bowl tightly with plastic wrap and refrigerate for at least 2 hours, or preferably overnight, to allow the flavors to meld and the salad to chill completely. Before serving, give the salad a gentle stir. Adjust seasonings if necessary, adding more salt, pepper, or sugar to taste. Serve cold.
Optional tips: For a richer flavor, use full-fat mayonnaise. Add a tablespoon of sweet relish for extra tang and sweetness. Some recipes include shredded carrots for added color and texture. Condensed milk may replace sugar for extra creaminess and sweetness.