Place the peeled and cubed potatoes in a large pot and cover with cold water by about an inch.
Bring the water to a boil over high heat, then reduce to medium and simmer for 10-12 minutes, or until the potatoes are tender when pierced with a fork.
While the potatoes cook, place the eggs in a saucepan and cover with cold water.
Bring to a boil over medium-high heat, then cover, remove from heat, and let sit for 10 minutes.
Drain the hot water from the eggs and place them in a bowl of ice water to cool for 5 minutes.
Drain the potatoes and transfer them to a large mixing bowl. Let them cool slightly.
Peel the cooled eggs and chop them into bite-sized pieces.
In a separate bowl, whisk together the mayonnaise, sour cream, Dijon mustard, apple cider vinegar, salt, and black pepper until smooth.
Add the chopped celery, red onion, and parsley to the potatoes.
Pour the dressing over the potato mixture and gently fold to combine.
Add the chopped eggs and gently fold them in, being careful not to break them up too much.
Taste and adjust seasoning with additional salt and pepper if needed.
Cover the salad and refrigerate for at least 1 hour before serving to allow flavors to meld.