Prep 30 mins
Cook 1 hr 15 mins
Submitted by Ingrid Quillen for Mascarpone Madness.
- 4 ounces dried porcini mushrooms
- 1 cup water, boiling
- 1 tablespoon butter
- 1 tablespoon olive oil, extra-virgin
- 1⁄4 cup parmesan cheese, grated
- 1 1⁄2 cups mascarpone cheese
- 1 cup whipping cream
- 3 garlic cloves, minced
- 1 pinch nutmeg, freshly grated
- 2 1⁄2 lbs potatoes, peeled and cut crosswise into 1/8-inch-thick slices
- 2 tablespoons parmesan cheese, grated
- Place porcini mushrooms in a medium bowl and cover with boiling water. Place a small bowl atop the mushrooms so that they stay submerged in the hot water. Soak for 20 minutes, then drain and coarsely chop the mushrooms.
- Place butter and oil in a medium skillet over medium heat. When the butter has melted add the mushrooms and saute just until they begin to brown, about 3 minutes. Sprinkle with salt and pepper and remove from heat. NOTE: this step can be done the day ahead. Refrigerate the browned mushrooms until ready to use.
- Whisk 1/4 cup parmesan, the mascarpone, whipping cream, garlic and nutmeg in a small bowl. Add salt and pepper to taste. NOTE: this step can be done the day ahead - simply cover the bowl and chill until ready to use.
- Preheat the oven to 325°F Butter a wide shallow 2-quart baking dish. Arrange 1/4 of the potato slices in the bottom of the dish. Sprinkle lightly with salt and pepper. Scatter 1/4 of the mushroom mixture over all. Follow with another layer of 1/4 of the potatoes, and another layer of 1/4 of the mushrooms. Spread half of the cheese mixture over all, shaking the dish if necessary to allow the layers to settle.
- Cover the cheese layer with a layer of potatoes, a layer of mushrooms, another layer of potatoes and the last of the mushrooms. Finally spread all of the remaining cheese mixture over the top. Sprinkle the 2 tablespoons of parmesan over all.
- Place the gratin dish on a rimmed baking sheet. Bake until the top is brown and the sauce is bubbling at the edges, about 1 hour and 15 minutes. Let rest 15 minutes before serving. NOTE: this dish can be made 2 hours ahead of time. Let stand at room temperature. Tent loosely with foil and rewarm at 300 F for 20 minutes.