Old-Fashioned Scalloped Potatoes

This scalloped potatoes recipe is a classic from Gourmet, simply made with softened onions, an easy roux, and thinly sliced potatoes. While the recipe calls for boiling potatoes, and medium-starch varieties like Yukon Gold will work well here, you can also use starchy potatoes like russets with creamy, comforting results. Wondering how to make scalloped potatoes that are customized to your taste? Feel free to sub out the cheddar for Gruyère, Emmenthaler, Fontina, or a mix, or add a pinch of nutmeg or dry mustard to the milk mixture. Any 3-quart vessel works for baking, whether it's a gratin or casserole dish or a deep skillet.