Scalloped potatoes are thinly sliced potatoes baked in cream or a simple white sauce until the slices are tender and the top is golden. They are a different dish from mashed potatoes, and they can be assembled a day ahead. See the Thanksgiving guide and Thanksgiving side dishes.
Slice evenly and use a warm sauce
Heat the oven to 350°F and butter a 9-by-13-inch dish, which usually serves 8 to 10 as a side. Peel 3 pounds of Yukon Gold or russet potatoes and slice them about ⅛ inch thick, with a knife or a mandoline, so the pieces cook at the same speed. In a saucepan, warm 2 cups of heavy cream or a white sauce made with 3 tablespoons of butter, 3 tablespoons of flour, and 2 to 2½ cups of milk, plus salt, pepper, and a little garlic or thyme. Layer the potatoes in the dish, pouring sauce over each layer. Classic scalloped potatoes are a cream-and-potato bake; potatoes au gratin are a closely related dish with more cheese and often a breadcrumb top. A modest layer of Gruyère or cheddar on the scalloped version is fine, but you do not need a second recipe to add a little cheese.
Bake until tender, or assemble ahead
Cover the dish with foil and bake 45 to 60 minutes, then uncover and bake 20 to 30 minutes more, until the top is golden and a knife slides through the center. Let it rest 10 to 15 minutes so the sauce thickens. To make it ahead, assemble the dish, cool it, cover it, and refrigerate it for up to a day. Bake it from cold, adding 15 to 20 minutes, and confirm the center is bubbling hot. Leftovers keep 3 to 4 days and should be reheated until steaming. Related: macaroni and cheese if you want another make-ahead casserole on the same oven schedule.
Do not rinse the slices so thoroughly that all of the surface starch is gone if you want a naturally thicker sauce, but do work quickly so the potatoes do not brown. A mix of cream and milk is lighter than all cream and still sets well. If the top browns before the center is tender, lay foil back over the dish and keep baking. Leftover scalloped potatoes reheat better in the oven or in a covered skillet than in a hard microwave blast, which can make the sauce separate. They are a good second potato dish if mashed potatoes are already on the menu, not a replacement for them.
Frequently asked questions
What is the difference between scalloped potatoes and au gratin?
Scalloped potatoes are usually baked in cream or a white sauce. Potatoes au gratin typically include more cheese and often a breadcrumb topping. The two are close cousins, not totally different dishes.
Can I make scalloped potatoes ahead?
Yes. Assemble the dish, refrigerate it for up to a day, and bake it until the center is bubbling and the slices are tender. Add extra time if it goes into the oven cold.
Why are my scalloped potatoes still hard in the middle?
The slices were probably too thick, or the dish was uncovered too soon and the top browned before the center cooked. Slice evenly and keep the pan covered for the first part of baking.
Helpful kitchen tools
- Pyrex Deep 9×13-Inch Glass Baking Dish with Lid — A 9-by-13-inch dish is the usual size for a Thanksgiving pan, and the lid helps if you assemble it ahead.
- HVH 9×13 Ceramic Baking Dish Set — A ceramic dish browns the top well and can go from oven to table.
- OXO Good Grips 2-Cup and 4-Cup Glass Measuring Cup Set — Useful for measuring cream or milk for the sauce.
- OXO Good Grips Bent Icing Spatula — Handy for spreading sauce between the potato layers.
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