Scalloped potatoes are thinly sliced potatoes layered in a baking dish with a creamy sauce made from butter, flour, milk, and seasonings. The dish is baked until the potatoes are fork-tender and the sauce is bubbly and lightly browned.
Au gratin potatoes are also thinly sliced potatoes layered in a baking dish and baked with a creamy sauce. However, au gratin potatoes are topped with a layer of cheese and breadcrumbs, and then baked until the potatoes are tender and the top is golden and crunchy.
