Place the quartered potatoes in a large pot and cover with cold, salted water (use 1 tablespoon salt). Bring to a boil over high heat.

Reduce heat and simmer for 15-20 minutes, or until potatoes are fork-tender. Drain thoroughly and let them cool slightly while you prepare the other ingredients.

While potatoes cool, chop the hard-boiled eggs, celery, and red onion. Place them in a large mixing bowl.

In a separate medium bowl, whisk together the mayonnaise, Dijon mustard, apple cider vinegar, fresh dill, 1 teaspoon salt, and 1/2 teaspoon black pepper until smooth and well combined.

Gently add the slightly warm, drained potatoes and the chopped eggs to the bowl with the celery and onion. Pour the dressing over the mixture.

Using a rubber spatula, gently fold the ingredients together until the potatoes are evenly coated. Be careful not to mash the potatoes too much; aim for some texture.

Cover the potato salad and refrigerate for at least 2 hours before serving; this allows the flavors to meld properly. Taste and adjust seasoning (salt/pepper) before serving.