Step 1: Cook the Macaroni: Bring a large pot of salted water to a boil. Add the macaroni and cook according to package directions until al dente. Overcooking will result in a mushy salad. Drain the macaroni well and rinse with cold water to stop the cooking process. This step is crucial for achieving the desired texture.
Step 2: Prepare the Dressing: In a large bowl, whisk together the mayonnaise, white vinegar, sugar, and milk until smooth. Adjust the sweetness and tanginess to your liking by adding more sugar or vinegar, a little at a time, tasting as you go.
Step 3: Combine Ingredients: Add the cooked macaroni to the bowl with the dressing. Gently fold until the macaroni is evenly coated. If using, stir in the finely chopped celery and onion.
Step 4: Season and Chill: Season with salt and pepper to taste. Cover the bowl with plastic wrap and refrigerate for at least 2 hours, or preferably overnight, to allow the flavors to meld and the salad to chill thoroughly. This resting period is essential for the salad to develop its signature taste and creamy texture.
Step 5: Adjust Consistency (If Needed): Before serving, check the consistency of the salad. If it seems too dry, add a little more milk, one tablespoon at a time, until it reaches the desired creaminess. Give it a final stir and serve cold.
For a tangier flavor, substitute apple cider vinegar for white vinegar. For a richer taste, use Japanese mayonnaise (Kewpie). Adding a small amount of grated carrot can provide a touch of sweetness and color.