This summer, in anticipation of the foodie film “Julie and Julia”, I revisited my copy of Julia Child’s iconic cookbook, “Mastering the Art of French Cooking”. As I flipped through the butter-stained pages, I came across a recipe that instantly activated my salivary glands: potato gratin. Potato gratin embodies all that is great in French cooking — liberal use of butter and cream and a focus on simple, quality ingredients. French technique, unfortunately, is not always so simple. This particular gratin involves making a béchamel, a sacred French sauce of thickened milk, butter and flour. But in the summer, when the only thing occupying my time is “NYC Prep”, spending an extra twenty minutes to make this sauce is well worth it. But I wanted to come up with a warm, cheesy, soft in the middle and crispy on the top, gratin that was quick to make. So here it is, a cheesy and easy potato mushroom gratin.
Potato and Mushroom Gratin
1 pound fresh wild or cremini mushrooms, trimmed and coarsely chopped
3 tablespoons unsalted butter
1 1/2 teaspoons minced garlic
3 pounds russet (baking) potatoes
1 1/2 cups heavy cream
1 1/2 cups whole milk
1 cup grated Swiss, Gruyere or other good melting cheese
¼ teaspoon nutmeg
salt, pepper (to taste)
Preheat the oven to 400ºF.
Cook the mushrooms with 3 tablespoons of butter in a large skillet over moderate heat, stirring, until the mushrooms are tender. Season with salt and pepper, then transfer to a bowl.
Peel the potatoes and cut them crosswise into 1/8-inch-thick slices. Bring the potatoes, cream, milk, salt, pepper, nutmeg, and 1 1/2 teaspoon of garlic to a boil in a large pot, stirring once or twice, then remove from heat.
Transfer half of the potatoes to a buttered gratin dish with a slotted spoon, spreading evenly. Spread mushrooms over the potatoes, then top with remaining potatoes. Pour the cooking liquid over the potatoes and sprinkle with cheese.
Bake until the top is golden brown and the potatoes are tender, 45–55 minutes.