1(8-ounce) package cream cheese(at room temperature; cut into small pieces)
½cup(1 stick butter)(at room temperature; cut into small pieces)
1cupgrated Parmesan cheese(divided)
2tablespoonsminced chives(plus additional minced chives to serve; optional)
Kosher salt and freshly ground pepper(to taste)
2tablespoonsdried plain bread crumbs or panko
Preheat the oven to 400 F.
Bring a large pot of salted water to a boil. Peel the potatoes and cut them into 2-inch pieces. Add the potatoes to the pot, adjust the heat so the water stays at a simmer, and simmer the potatoes for about 20 to 25 minutes until they are very tender, almost falling apart when you slide a knife into them. Drain well, then mash them into a large bowl using a ricer, a food mill, or a potato masher.
While the potatoes are cooking, bring the cream and milk to a simmer in a small pot. When the potatoes are mashed or riced, pour in the hot milk mixture, add the cream cheese and butter, and stir until everything is very well combined and fairly smooth. Stir in half of the Parmesan, chives (if using), and salt and pepper until well blended.
Transfer to a large 4-quart shallow baking dish and swirl the top attractively. In a small bowl, mix together the remaining ½ cup Parmesan and the breadcrumbs. Sprinkle them over the top.
Bake for 20 minutes until the top is golden brown. If you want a more browned top, you can change the oven setting to broil and give it another few minutes, watching carefully to make sure it doesn’t get too brown. Serve hot, with additional chives sprinkled over the top if desired.
After you transfer the mashed potatoes to the shallow baking dish, use a butter knife or an offset spatula to swoop the top, making peaks and valleys. This will not only make the dish look more appealing in general (is that even possible?), it will encourage the top edges of the swirls to brown in the oven, which looks especially inviting.
This recipe serves a lot of mashed potato-loving folks. You can cut the recipe in half easily if you have a smaller crowd. Just use a smaller baking dish, about 2 quarts vs. 4, if you are making a smaller batch.
If you want a more browned top, after the potatoes are hot throughout, you can change the oven setting to broil and give it another few minutes, watching carefully to make sure it doesn’t get too brown.
If you want to make this ahead, you can assemble the whole casserole, bread crumbs, and all, and let it sit at room temperature for up to 6 hours before baking. Or you can make the casserole up to the point where you sprinkle over the breadcrumb topping and refrigerate it, covered, for up to 3 days. Allow to come to room temp before baking, and sprinkle over the topping just before you put it in the oven. If you don’t have time to bring it to room temperature, plan to add another 15 minutes or so to the baking time.