Fill a Dutch oven with water and bring to a boil over medium-high heat. Add the potatoes and cook 30 minutes or until tender. Drain well and cool. Cut the potatoes into cubes and transfer to a serving bowl. Add the eggs, onions and celery.
In a medium bowl, stir together the mayonnaise, dressing, mustard, salt and celery seeds. Gently toss over the potato mixture. Cover and refrigerate at least 2 hours before serving.
Recipe by The Tennessee Magazine at https://www.tnmagazine.org/summer-pairings/