Step 1: Cook the Macaroni: Boil the elbow macaroni according to package directions until al dente. Overcooking will result in a mushy salad. Drain well and rinse with cold water to stop the cooking process. This step is crucial for preventing the macaroni from sticking together.
Step 2: Prepare the Dressing: In a large bowl, whisk together the mayonnaise, milk, sugar, vinegar, salt, and pepper until smooth and creamy. The dressing should be slightly sweet and tangy. Adjust the sugar or vinegar to taste, ensuring a well-balanced flavor profile.
Step 3: Combine Ingredients: Add the cooked and cooled macaroni, finely diced onion, and celery (if using) to the bowl with the dressing. Gently fold all ingredients together until the macaroni is evenly coated. Avoid overmixing, which can cause the macaroni to break apart.
Step 4: Chill Thoroughly: Cover the bowl with plastic wrap and refrigerate for at least 2 hours, or preferably overnight. This allows the flavors to meld and the salad to chill completely. Chilling is essential for achieving the desired texture and taste.
Step 5: Adjust and Serve: Before serving, check the consistency of the salad. If it seems dry, add a little more milk to moisten it. Taste and adjust seasoning as needed. Serve cold and enjoy!
Optional Tip: For a richer flavor, try using a combination of mayonnaise and sour cream in the dressing. Some variations include a tablespoon of grated carrot or a small can of drained, flaked tuna.