Cook the elbow macaroni according to package directions until al dente. Drain well and rinse with cold water to prevent sticking. Set aside to cool slightly.

In a large mixing bowl, whisk together the mayonnaise, sour cream, Dijon mustard, apple cider vinegar, salt, and black pepper until well combined and smooth.

Add the cooked and cooled macaroni, thawed frozen peas, finely chopped celery, and finely chopped red onion to the bowl with the dressing. Stir gently to coat all ingredients evenly.

Cover the bowl and refrigerate for at least 30 minutes to allow the flavors to meld before serving. For best results, chill for a few hours.