01 - Place cubed potatoes in a large pot and cover with cold, salted water. Bring to a boil over medium-high heat. Reduce heat and simmer for 10-12 minutes until fork-tender.
02 - Drain potatoes thoroughly and spread on a baking sheet. Let cool for 10 minutes to prevent dressing from becoming watery.
03 - Whisk together mayonnaise, sour cream, Dijon mustard, apple cider vinegar, salt, and pepper in a large mixing bowl until smooth and well combined.
04 - Add cooled potatoes, celery, red onion, parsley, and chives to the dressing. Gently toss to coat all ingredients evenly without mashing the potatoes.
05 - Fold in chopped hard-boiled eggs if using. Taste and adjust seasoning with additional salt and pepper as needed.
06 - Cover bowl and refrigerate for at least 1 hour to allow flavors to meld. Garnish with additional fresh herbs before serving if desired.