Repeat the layering process two more times: potatoes, then cheese, then cream, finishing with a generous layer of cheese on top. Gently press down on the layers with your hands or the back of a spatula to help everything settle and ensure the cream is distributed.
Cover the baking dish tightly with foil and place it on the middle rack of the preheated oven. Bake for 35–40 minutes, until the potatoes are starting to soften and the cream is bubbling around the edges.
Remove the foil and continue baking for another 20–25 minutes, or until the top is deeply golden, the cheese is melted and browned in spots, and a knife slides easily through the potatoes with no resistance.
Let the scalloped potatoes rest for at least 10–15 minutes before serving. This resting time allows the creamy, cheesy sauce to thicken slightly and the layers to set, making it easier to cut neat squares or scoops.
Because this recipe is built on just four ingredients, it’s a great canvas for small tweaks. For a slightly lighter version, you can use half-and-half in place of heavy cream, understanding that the sauce will be a bit less thick and luxurious. If you enjoy a more pronounced cheese flavor, try using a mix of sharp cheddar and Gruyère, or add a handful of Parmesan to the top layer for extra browning and a nutty finish. You can also play with the salt element: instead of salting only the cream, lightly season each potato layer as you build the dish for more even distribution. For subtle aromatics without adding more ingredients, rub the baking dish with a cut clove of garlic before layering the potatoes; it leaves just a whisper of flavor. If you’re cooking ahead, bake the dish until just tender, cool it, then reheat covered at 350°F until hot and bubbling—uncover for the last 10 minutes to refresh the crust. Finally, if your oven runs hot or the top browns too quickly, tent the dish loosely with foil toward the end of baking to protect the cheese while the potatoes finish cooking.
