Preheat the oven to 325 degrees F. Butter a 2-quart baking dish and set aside.
Place the potatoes in a large pot filled with salted water. Bring to a boil and cook until fork tender, 10 to 15 minutes. Drain the potatoes and transfer to the bowl of a stand mixer fitted with the paddle attachment. Beat the potatoes until chunky, then add the cream cheese, sour cream and 4 tablespoons of the butter. Whip until smooth. Add the chives and some salt and pepper to taste.
Using a spatula, transfer the potatoes to the buttered baking dish and spread evenly. Cut the remaining 2 tablespoons of butter into cubes, then sprinkle them over the top. (At this point it can be refrigerated until guests arrive.)
Bake, covered with aluminum foil, for 15 minutes, then uncover and bake for another 20 minutes.
Remove from the oven and let sit for 10 minutes. Sprinkle with additional chives and serve hot.
Copyright 2016 Cooking Channel, LLC. All rights reserved.