Place the potatoes in a large pot and cover with cold water. Bring to a gentle boil over medium heat, and cook until just tender when pierced with a fork, about 15-20 minutes. Drain well in a colander and let cool slightly.
While the potatoes are still warm, peel them if desired, or leave the skins on for texture. Cut the potatoes into bite-sized chunks and transfer to a large mixing bowl.
Add the finely chopped red onion, sliced celery, and chopped fresh dill to the bowl with potatoes. Mix gently to distribute the ingredients evenly.
In a small bowl, whisk together mayonnaise, apple cider vinegar, and Dijon mustard until smooth and well combined.
Pour the dressing over the warm potatoes and vegetables. Gently fold everything together, ensuring all ingredients are coated evenly without breaking the potatoes apart.
Season the potato salad with salt and freshly ground pepper to taste. Taste and adjust the seasoning if needed, adding more vinegar for tang or salt for flavor.
Transfer the salad to a serving bowl, cover, and refrigerate for at least 1 hour to allow flavors to meld. The salad will develop a slightly tangy and creamy flavor with a hearty, textured feel.
Before serving, give the potato salad a gentle stir. Serve chilled, garnished with extra dill or herbs if desired, and enjoy this classic, creamy dish.
