Potatoes au gratin meant something else entirely. In the late 19th century, this term referred to mashed potatoes topped with grated cheese and cooked in the skin. Over the next century, the recipe evolved into a baking dish, eventually evolving into the creamy gratin we expect today.
Most contemporary American schnitzel recipes closely resemble French gratin dauphinois. A version of this recipe appears in the famous Julia Child Mastering the Art of French Cooking cookbook. There, she translates gratin dauphinois as “potatoes au gratin with milk, cheese, and a pinch of garlic.” It is the excellent version of Julia that we use as a starting point to develop our best potato scallops recipe.
Like dauphinois au gratin, potatoes au gratin include thinly sliced potatoes, milk and/or cream, and a crisp, golden top layer fresh from the oven. But there’s actually little consensus on whether scalloped potatoes should include cheese and how scalloped potatoes differ from a gratin or casserole. Various sources insist that scalloped potatoes should not include cheese, but most popular internet scalloped potato recipes include cheese.
After weighing the pros and cons, we decided to add cheese, because scalloped potato fans expect a lot, and baked potatoes taste delicious with a layer of fizzy cheese on top. We considered using either Gruyère or Cheddar, and after trying both, we opted for Gruyère, for its sweet, nutty flavor and A+ melting. If you can’t find Gruyère (or don’t like it), Comté or a quality Swiss cheese are also good options; you just want a cheese that has a deep flavor, a nice firmness, and doesn’t get too greasy when melted.
When it comes to potatoes, we’ve opted to use Yukon Golds instead of the more starchy Russets. While Russets can break easily when sliced and cooked, Yukons hold up well and have a thicker, creamier texture.
Now, what to cook these potatoes with? Milk can curdle when simmering in the oven. The taste is still good, but visually unpleasant. Some recipes solve this problem by preparing a bechamel, or milk sauce (milk thickened with a roux of butter and flour). We have chosen to simplify the process by using cream instead. It gives a rich, savory flavor, requires less work, and is gluten-free.
You could call it a day just for cream, but a couple of bonuses go a long way. To give it more flavor, we infuse it with a bay leaf and a little minced garlic. Although these ingredients are filtered and discarded, their subtle flavor perfumes the finished dish. Fresh thyme is also used to add depth as it is sprinkled between the potato layers. Sure, you can use rosemary or sage if you prefer, but we’ve found that fresh thyme works best to complement the potatoes without overpowering the dish.
One last important note: When the scallops come out of the oven, you should wait 20-30 minutes before serving. This is a dish that needs some time to settle and actually tastes better hot than hot. —Josh Cohen