Ingredients
1/2 ounce dried mushrooms, such as porcini (about 1/2 cup)
2 cups boiling water
1 1/2 tablespoons extra-virgin olive oil
1 medium onion, halved and thinly sliced into half-moons
3 cloves garlic, minced
1 celery stalk, finely chopped (about 1/2 cup)
1 pound cremini or white mushrooms, caps and stems thinly sliced lengthwise (about 6 cups)
1/2 teaspoon coarse salt
1/2 cup dry white wine
2 cups Homemade Chicken Stock or low-sodium canned broth
1 tablespoon finely chopped fresh tarragon, plus 4 sprigs for garnish
4 large eggs
1 ounce Parmesan cheese, thinly shaved with a vegetable peeler
Freshly ground black pepper
Preparation
Soak dried mushrooms in boiling water, covered, until soft, about 20 minutes. Lift out mushrooms; squeeze over liquid. Finely chop; set aside. Pour liquid through a fine sieve into a bowl; reserve.
Heat oil in a medium saucepan over medium heat until hot but not smoking. Add onion, garlic, and celery; cook, stirring occasionally, until soft, about 8 minutes. Add fresh mushrooms and salt; cook, stirring occasionally, until most of liquid has evaporated and mushrooms are soft, about 12 minutes. Raise heat to high. Add wine, reserved mushrooms and liquid, stock, and 1 1/2 cups water; bring to a simmer. Reduce heat to medium-low; cook 30 minutes. Add chopped tarragon.
Fill another medium saucepan 3/4 full with water; bring to a bare simmer over medium heat. Crack eggs into pan; cook until whites are set but yolks are slightly runny, 3 to 4 minutes.
Divide soup among 4 bowls. Transfer an egg to each bowl; divide cheese among eggs. Season each serving with pepper, and garnish with a tarragon sprig.
