YUKON GOLD POTATO AND WILD MUSHROOM GRATIN WITH BLUE CHEESE

Yukon Gold Potato and Wild Mushroom Gratin with Blue Cheese image

Yield Serves 6 to 8

Number Of Ingredients 8

5 ounces crumbled blue cheese (such as Stilton, Gorgonzola or Maytag blue; about 1 1 /2 cups), room temperature
2 1/2 cups whipping cream
1 teaspoon salt
1/2 teaspoon pepper
1 1/2 tablespoons butter
1 pound mixed fresh wild mushrooms (such as chanterelle, morel, portobello, stemmed shiitake, oyster, crimini or hedgehog), thickly sliced
1 1/2 teaspoons chopped fresh thyme or 3/4 teaspoon dried
2 pounds Yukon Gold potatoes, peeled, very thinly sliced into rounds

Steps:

Position rack in top third of oven and preheat to 400°F. Butter 13 x 9 x 2-inch glass baking dish. Place cheese in medium bowl; add 1 cup/2 cream. Using fork, mash mixture to chunky paste. Mix in 1 teaspoon salt and 1/2 teaspoon pepper. Mix in remaining 2 cups cream.
Melt butter in heavy large pot over medium-high heat. Add mushrooms and herbs; sauté until mushrooms are tender and liquid cooks away, about 8 minutes. (Cheese sauce and mushrooms can be made 8 hours ahead. Cover separately and chill.)
Arrange half of potatoes on bottom of prepared dish. Spoon 3/4 cup cheese sauce evenly over. Top with all of mushroom mixture, 3/4 cup cheese sauce, then remaining potatoes. Top with remaining cheese sauce. Cover dish with foil.
Bake gratin 30 minutes. Uncover and bake until potatoes are tender, top is golden brown and sauce is thickened, about 30 minutes longer. Let stand 10 minutes; serve hot.