SWEET POTATO AND GRUYèRE GRATIN

Sweet Potato and Gruyère Gratin image

This rich, cheese-laden gratin is a more savory take on the usual Thanksgiving sweet potato casserole, with sage and rosemary giving it an herbal bite. If you'd like to make it partway ahead, you can peel and slice the potatoes the day before; store in a sealable plastic bag in the fridge. You can also simmer the cream mixture (don't add eggs) and grate the cheese the day before as well, storing them covered in the refrigerator.

Provided by Melissa Clark

Categories casseroles, side dish

Time 1h30m

Yield 12 servings

Number Of Ingredients 12

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Ingredients

3 tablespoons unsalted butter, softened, for pan and foil
1/3 cup grated Parmesan
2 cups heavy cream (or half-and-half)
3 tablespoons fresh sage, chopped
1 tablespoon fresh rosemary, finely chopped
3 fat cloves garlic, grated or minced
1/4 teaspoon freshly grated nutmeg
1 1/2 teaspoons kosher salt, plus more as needed
3 large eggs, lightly beaten
3 pounds sweet potatoes (about 4 large or 5 medium), peeled
Freshly ground black pepper, to taste
1 2/3 cups/6 1/2 ounces grated Gruyère

Steps:

Heat oven to 400 degrees and generously butter a 9-by-13-inch baking pan or shallow gratin dish. Butter a piece of foil large enough to cover top of pan. Sprinkle Parmesan all over bottom of pan.
In a medium pot, bring cream, sage, rosemary, garlic, nutmeg and a pinch of salt to a simmer. Simmer until reduced by 1/4, about 10 minutes.
In a large, heatproof bowl, whisk eggs just enough to break them up. Slowly pour hot cream into eggs to combine, whisking while pouring, and reserve the mixture.
Meanwhile, using a mandoline or sharp knife, slice the potatoes into 1/8-inch-thick rounds.
Place 1 layer of potatoes in the pan, slightly overlapping as you go, using about a third of the slices. Sprinkle with 1/4 teaspoon salt and pepper to taste, then pour 1/3 of the egg mixture over potatoes. Top with 1/2 cup Gruyère. Repeat with another layer of potatoes, 1/2 teaspoon of salt, pepper and 1/3 egg mixture. Top with 1/2 cup Gruyère. Top with remaining potatoes, 1/4 teaspoon salt, pepper to taste, and remaining egg mixture (but not the remaining cheese). Press down to compact the potatoes. Cover with foil and bake until potatoes are tender, about 40 minutes, then remove foil, sprinkle top with remaining 2/3 cup Gruyère and bake until browned and bubbling, 25 to 30 minutes. Let cool slightly, then serve.

Nutrition Facts : @context http, Calories 363, UnsaturatedFat 9 grams, Carbohydrate 26 grams, Fat 25 grams, Fiber 4 grams, Protein 10 grams, SaturatedFat 15 grams, Sodium 444 milligrams, Sugar 6 grams, TransFat 0 grams