Place potato chunks in a large pot and cover with cold water. Add 1 teaspoon salt. Bring to a boil over high heat, then reduce to a simmer and cook for 12-15 minutes until potatoes are tender when pierced with a fork.

Drain potatoes thoroughly in a colander. Let them cool for about 10 minutes until they're no longer steaming hot but still warm.

While potatoes cool, make the dressing: In a medium bowl, whisk together mayonnaise, sour cream, dill, Dijon mustard, apple cider vinegar, and black pepper until smooth.

In a large mixing bowl, combine the cooled potatoes, diced celery, diced red onion, and chopped hard-boiled eggs (if using).

Pour the dressing over the potato mixture. Gently fold everything together until evenly coated, being careful not to mash the potatoes.

Taste and add additional salt if needed. Cover the bowl and refrigerate for at least 1 hour before serving to allow flavors to meld.