Preparation Cook potatoes in large pot of boiling salted water just until tender, about 12 minutes. Drain. Transfer potatoes to large bowl. Drizzle vinegar over hot potatoes. Cool to room temperature. Mix eggs, onion, celery and parsley into potatoes. Whisk mayonnaise, sour cream and mustard in medium bowl. Mix into potato mixture. Season with salt and pepper. (Can be made 1 day ahead. Cover and refrigerate.)
Preparation Cook potatoes in large pot of boiling salted water just until tender, about 12 minutes. Drain. Transfer potatoes to large bowl. Drizzle vinegar over hot potatoes. Cool to room temperature. Mix eggs, onion, celery and parsley into potatoes. Whisk mayonnaise, sour cream and mustard in medium bowl. Mix into potato mixture. Season with salt and pepper. (Can be made 1 day ahead. Cover and refrigerate.)