My neighbor brought this to our potluck and I had to get the recipe. Just 4 ingredients and it feeds a crowd.

This oven baked 4-ingredients Swiss cheese potato gratin is exactly the kind of dish that shows up at a neighborhood potluck and quietly steals the show. It’s rich, bubbly, and deeply comforting, with thinly sliced potatoes tucked into a creamy base and blanketed in nutty Swiss cheese. Gratins in various forms have roots in French country cooking, where simple pantry staples—potatoes, dairy, and cheese—are transformed into something luxurious. Here, I’ve streamlined that idea into a version you can assemble in minutes, slide into the oven, and forget about until the top is golden and the edges are crisp. It feeds a crowd, travels well, and requires only four ingredients you can find in any grocery store.

Serve this gratin alongside simple roasted or grilled meats—roast chicken, pork tenderloin, or a seared steak all work beautifully. A crisp green salad with a sharp vinaigrette balances the richness, and steamed or roasted vegetables like green beans, broccoli, or Brussels sprouts round out the plate. For a potluck or holiday table, pair it with glazed ham, a platter of sliced roast beef, or even as a hearty side for baked salmon. Leftovers reheat well and make a cozy lunch with just a bright salad or a cup of tomato soup.

Servings: 10

3 pounds russet or Yukon Gold potatoes, peeled and very thinly sliced

Preheat your oven to 375°F (190°C). Lightly grease a 9x13-inch (3-quart) white casserole or baking dish so the potatoes release easily and the edges can crisp and brown.

Peel the potatoes and slice them very thinly, about 1/8 inch thick. You can use a sharp knife or a mandoline if you have one. Keep the slices in a large bowl; no need to rinse, as the surface starch helps the gratin thicken.

Pour the heavy cream over the sliced potatoes and sprinkle with the kosher salt. Toss gently with clean hands or a large spoon until every slice is coated and the salt is evenly distributed.

Spread half of the cream-coated potato slices in an even layer in the prepared baking dish, arranging them so they overlap slightly but lie mostly flat. Sprinkle half of the shredded Swiss cheese (about 1 1/2 cups) evenly over this first layer.

Arrange the remaining potatoes over the cheese in a second even layer, again overlapping slightly. Pour any cream left in the bowl evenly over the top so it seeps down between the layers.

Sprinkle the remaining Swiss cheese evenly over the surface, making sure to cover the potatoes all the way to the edges. This helps create those crisp, browned edges and a bubbly, golden top.

Cover the dish tightly with foil and bake for 45 minutes, until the potatoes are starting to soften and the cream is hot and steamy. This covered time lets the potatoes cook through without the top over-browning.

Remove the foil and continue baking, uncovered, for 25–35 minutes, or until the top is deeply golden, the cheese is bubbling, and a knife slides easily through the center of the potatoes. The edges should be browned and slightly crisp.

Let the gratin rest for at least 15 minutes before serving. This rest allows the creamy sauce to thicken slightly and makes it easier to cut neat squares that hold together when you lift them from the casserole dish.

Carry the gratin to the table or potluck in the same baking dish. Serve warm, scooping or slicing generous portions so everyone gets some of the bubbly, golden Swiss cheese top and the creamy layers beneath.

For a slightly lighter version, you can swap part of the heavy cream for whole milk or half-and-half, keeping at least half of the volume as cream so the texture stays lush. If you prefer a more assertive flavor, choose a stronger Swiss-type cheese like Gruyère or Emmental, or mix in a small portion of smoked Swiss while still keeping the total cheese amount the same. To make ahead for a potluck, bake the gratin fully, cool, cover, and refrigerate; reheat covered at 350°F until hot, then uncover for the last 10–15 minutes to re-crisp the top. For smaller households, assemble the recipe in two 8-inch square dishes and bake one now while freezing the other (tightly wrapped) before baking; thaw in the refrigerator overnight and bake as directed. If your oven tends to brown quickly, move the dish to a lower rack or tent loosely with foil once the top is golden so the potatoes can finish cooking without over-darkening the cheese.