Chef Charlie Palmer suggests this gratin as a standout side for the Thanksgiving table, and we agree. In it, he switches up the standard potato gratin by adding parsnips, which give it a sweet vanilla note, and fresh breadcrumbs for an extra-crunchy topping. To make it, put together a quick cream and garlic sauce on the stovetop, then layer that in a baking dish with sliced potatoes, parsnips, and Emmentaler cheese and bake, sprinkling on the breadcrumb topping toward the end to crisp.
Special equipment: A good-quality mandoline is indispensable in a professional kitchen, and is useful here. Watch your fingers: The ingredients you’re going to slice should be cupped in the palm of your hand, not held with your fingertips. For even slices, apply more forward than downward pressure. (Pressing down too hard will yield vegetables thicker on one side than the other, as well as feed your fingers into the blade.)
Game plan: The gratin can be made ahead through step 5, covered, and refrigerated. To serve, rewarm it covered in a 350°F oven for about 25 minutes, then continue with step 6.
- 1Heat the oven to 425°F and arrange a rack in the middle. Lightly coat a 2-1/2-quart baking dish with butter and set aside.
- 2Heat the olive oil in a small saucepan over medium heat until shimmering, about 3 minutes. Add the garlic and cook, stirring occasionally, until softened but not browned, about 2 minutes. Add the cream and salt, season with pepper and a pinch of nutmeg, stir to combine, and cook until the cream is simmering but not boiling; remove from the heat and set aside.
- 3Peel, trim, and slice the parsnips crosswise into 1/8-inch-thick rounds. Place in a large mixing bowl. Peel the potatoes, slice crosswise into 1/8-inch-thick rounds, and add to the bowl. Toss the potatoes and parsnips until evenly combined and set aside.
- 4Evenly layer half of the potato-parsnip mixture in the prepared dish. Dot with half of the butter and sprinkle with half of the cheese. Evenly layer the remaining half of the potato-parsnip mixture in the dish and pour the warm cream mixture evenly over the top. Dot with the remaining butter and sprinkle with the remaining cheese.
- 5Cover the dish with foil and bake until the potatoes and parsnips are tender when pierced with a fork, about 35 to 40 minutes.
- 6Remove the foil and sprinkle the breadcrumbs evenly over the gratin, pressing them down lightly with the back of a spatula (this helps them absorb some of the moisture and keeps them from browning too fast). Return the gratin to the oven uncovered and bake until the top is golden brown, about 10 minutes more. Let rest at least 5 minutes before serving.