Ingredients
2 oz dried porcini mushrooms 1 C boiling water 2 T (1/4 stick) butter 2 t T extra virgin olive oil 1/4 cup plus 2 T grated parmesan cheese 1 1/2 C mascarpone cheese (from about 1 1/2 seven ounce containers) 1 C whipping cream 3 garlic cloves, chopped Pinch of freshly grated nutmeg 2 1/2 pounds russet potatoes (about 5 large), peeled, cut crosswise into 1/8" thick slices
|
Instructions
Place porcini mushrooms and 1 cup boiling water in medium bowl. Place small bowl atop mushrooms to keep submerged. Let soak 20 minutes. Drain and coarsely chop mushrooms.Melt butter with olive oil in medium skillet over medium heat. Add chopped mushrooms and saute until beginning to brown, about 3 minutes. Sprinkle with salt and pepper. Remove from heat. Whisk 1/4 cup parmesan chese and next four ingredients in small bowl; season with salt and pepper. Mushrooms and cheese mixture can be prepared 1 day ahead. Cover separately and chill. Preheat oven to 325 degrees. Butter a wide shallow 2 quart baking dish. Arrange 1/4 of potato slices in bottom of dish. Sprinkle lightly with salt and pepper. Scatter 1/4 of mushrooms over. Spread 1/2 of cheese mixture over, shaking dish to settle. Repeat with remaining potatoes and mushrooms in 2 layers each; spread remaining cheese mixture over. Sprinkle 2 tablespoons parmesan over. Place baking dish on rimmed baking sheet. Bake gratin until top is brown and sauce is bubbling at edges, about 1 hour and 15 minutes. Let gratin rest 15 minutes before serving. Can be made 2 hours ahead. Let stand at room temperature. Tent loosely with foil and re-warm in 300 degree oven for 20 minutes.
|