Cool, creamy macaroni salad with crisp vegetables and a tangy dressing is a family-favorite vegetarian cookout side. This classic picnic dish is easy to make ahead for any gathering.
Bring a large pot of salted water to a boil over high heat, add macaroni, and cook for 7–8 minutes until just al dente. Drain well and rinse with cold water to cool.
Dice celery, red bell pepper, carrot, and red onion into small, even pieces for balanced crunch and texture.
In a large mixing bowl, whisk together mayonnaise, sour cream, apple cider vinegar, Dijon mustard, sugar, salt, and black pepper until smooth and well blended.
Add cooled macaroni and all vegetables to the dressing; gently fold with a spatula to coat every piece evenly without breaking the pasta.
Cover and refrigerate for at least 1 hour to allow flavors to meld and the salad to chill completely before serving. Toss lightly again before plating.