Cooking with Dried Boletes (aka Porcini):
As a rule, 3 ounces of dried boletes will equal 1 pound of rehydrated mushrooms. Much variation is found in chefs' opinions as to how long to soak them. On the average they are soaked for about 15 minutes in warm water to cover. Heat hastens the rehydration process. The length of time depends upon the thickness of the slices. Squeeze dry, but be sure to save the liquid in the bowl to preserve the rich flavor for use in your dish.
Dried boletes have a deep, rich taste that dominates soups and sauces for polentas and pastas. When you cook with dried B. edulis your kitchen will be redolent with its powerful fragrance. The essence of the mushroom persists in the cooking pot even after the pot has been washed and dried.
Cut mushrooms into desired sizes after soaking. In general, the larger the pieces, the more flavor. Some chefs prefer to saute them quickly in olive oil and butter before adding them to the dish they are preparing. Add the remaining soaking liquid to your food preparation by carefully pouring off the concentrated essence from the top, discarding any residual matter such as sand or soil at the bottom of the vessel.
Savory Mushroom and Gruyère Strata
2 Tbsp olive oil, plus more for the baking dish
1 pound assorted fresh wild or cultivated mushrooms (chanterelles, hen of the woods, crimini, button etc), thinly sliced
1 cup chopped onion or leeks
1 oz dried bolete mushrooms, reconstituted, drained & coarsely chopped, liquid reserved
1 Tbsp fresh thyme or sage
2 garlic cloves, chopped
1/4 cup dry sherry (optional)
2 cups milk
4 large eggs
salt and freshly ground black pepper
12 slices white bread, crusts trimmed
3/4 cup grated Gruyère cheese
3/4 cup grated Parmesan cheese
Lightly oil a 13 x 9 inch baking dish. Heat 2 tablespoons olive oil in a large pan over medium-high heat. Add the onion or leeks and cook for 2-3 minutes. Add the sliced fresh mushrooms and reconstituted dried mushrooms and continue to cook, stirring frequently, for another 5 minutes. Stir in the thyme and garlic and season with salt and pepper. Remove from the heat, allow to cool slightly and place in a large bowl.
Pour the dry sherry and 1 cup of the reserved mushroom liquid into the same pan used to cook the mushrooms. Bring to a boil and cook until reduced by half. Remove from heat.
Whisk the milk and eggs together in a bowl until thoroughly blended. Stir in the sherry-mushroom liquid and season with salt and pepper.
Arrange 6 slices of bread on the bottom of the oiled baking dish. Top with the mushroom mixture, half of the Gruyère, and half of Parmesan cheese. Top with the remaining bread slices. Pour the egg mixture over the top and press gently to make sure that the bread is entirely saturated. Cover place in the refrigerator for at least one hour.
Preheat the oven to 350°F. Top with the remaining Gruyère and Parmesan cheese and bake uncovered until the top is golden brown, about 40 minutes. Serve hot.