01 - Place potatoes in a large pot and cover with cold, salted water. Bring to a boil, then simmer for 10 to 12 minutes until just fork-tender. Drain and allow to cool slightly.
02 - In a large bowl, whisk together mayonnaise, sour cream, Dijon mustard, apple cider vinegar, dill, salt, and pepper until smooth.
03 - Add the cooked potatoes, celery, red onion, and scallions to the dressing. Gently toss until evenly coated.
04 - If desired, fold in chopped hard-boiled eggs and diced pickles.
05 - Cover and refrigerate for at least 1 hour to allow flavors to develop.
06 - Taste the salad and adjust seasoning if needed. Garnish with additional fresh dill before serving.