WILD MUSHROOM AND POTATO GRATIN

Wild Mushroom and Potato Gratin image

Wild mushrooms add a luxurious dimension to this comforting, almost classic potato gratin. There is no cream here, just milk mixed with porcini broth (the result of soaking dried porcinis for 30 minutes in boiling water). You can use a mix of wild mushrooms, or just one type. Sauté them with onion or shallots, garlic and savory herbs (thyme and rosemary or sage), season them well and toss with the potatoes. The gratin requires 1 1/2 hours in the oven; first you will doubt that all of the liquid will be absorbed by the potatoes, and about halfway through you will be convinced that the finished dish will be watery and the potatoes hard. But by the end, once all the bubbling has subsided, the soft potatoes will have imbibed all of the flavorful liquid in the dish, and the top and edges of the gratin will be crusty, the way a gratin should be.

Provided by Martha Rose Shulman

Time 2h

Yield Serves 6 to 8

Number Of Ingredients 15

Ingredients

1/2 ounce (about 1/2 cup) dried porchinis
2 tablespoons extra virgin olive oil
1 pound wild mushrooms, torn into smaller pieces if large, cleaned if necessary
1/2 cup finely chopped onion or 2 shallots, minced
2 garlic cloves, minced, plus 1/2 garlic clove, intact
1 teaspoon minced fresh thyme leaves, chopped
1 teaspoon minced fresh rosemary or sage
Salt
1/4 cup dry white wine
Freshly ground pepper
1 1/2 pounds russet potatoes, golden potatoes or Yukon golds, scrubbed, peeled if desired, and sliced about 1/4 inch thick
1 cup, tightly packed, grated Gruyère cheese (4 ounces )
Salt to taste
Freshly ground pepper
2-1/2 cups milk (whole or 2 percent)

Steps:

Place the dried porcinis in a bowl or a pyrex measuring cup and pour on 1 1/2 cups boiling water. Soak for 30 minutes. Line a strainer with cheesecloth and place over a bowl. Drain mushrooms, then squeeze in cheesecloth to extract juices. Rinse several times and chop medium-fine. Measure out 1 cup of broth.
Meanwhile heat oven to 375 degrees. Rub inside of a 3-quart gratin dish or baking dish all over with the cut half garlic clove and lightly oil with olive oil. Heat oil in a wide, heavy nonstick skillet over medium heat. Add onion or shallots and cook gently until just tender, 3 to 5 minutes. Turn up heat to high and add mushrooms. Cook, stirring, until they begin to sweat, 2-3 minutes, reduce heat to medium, and add minced garlic, thyme, rosemary or sage and dried porcinis. Cook, stirring, until fragrant, about 30 seconds. Season mushrooms with salt and pepper and continue to cook over medium heat until soft, about 5 more minutes. Add wine and cook, stirring, until it is no longer visible in the pan. Taste and adjust seasoning.
In a large bowl combine potatoes, mushrooms, half the cheese, and salt and pepper. Arrange in an even layer in gratin dish.
Combine milk and mushroom broth. Season generously with salt and pour over the potatoes and mushrooms. Press the vegetables down into the liquid. Bake 1 hour. Every 20 minutes remove gratin dish and press potatoes and mushrooms down into the liquid with the back of a large spoon. After 1 hour, sprinkle on remaining cheese and bake for another 30 minutes, until top is golden and the sides crusty. Remove from the oven and allow to sit for 10 to 15 minutes before serving. Serve hot or warm.

Nutrition Facts : @context http, Calories 242, UnsaturatedFat 5 grams, Carbohydrate 26 grams, Fat 11 grams, Fiber 4 grams, Protein 10 grams, SaturatedFat 5 grams, Sodium 594 milligrams, Sugar 6 grams