Place whole red potatoes in a large pot and cover with cold, salted water. Bring to a boil, then simmer for 10-20 minutes until fork-tender.

Transfer cooked potatoes to an ice bath to cool for 5-10 minutes. Cut into bite-sized cubes.

Steam eggs for 15 minutes and plunge them into an ice water bath. Once cool, peel and chop the eggs.

In a mixing bowl, combine mayonnaise, sour cream, and Dijon mustard until smooth.

In a bowl, add cubed potatoes, chopped eggs, celery, red onion, dill, and chives. Toss with dressing and season to taste.

Serve immediately or chill for 30 minutes to allow flavors to develop.