Ingreadient

• 3 cups boiling water, divided
• 2 cups dried porcini mushrooms (about 1½ ounces)
• 3 tablespoons cornstarch
• 1¾ teaspoons salt
• 1½ teaspoons ground pepper, plus more for garnish
• 1½ teaspoons dried thyme
• ½ teaspoon dried tarragon
• 2 tablespoons extra-virgin olive oil
• 2 cups sliced shallots (about 8 ounces)
• 2 tablespoons finely chopped garlic
• ⅔ cup dry sherry
• 3 pounds assorted fresh mushrooms (such as cremini, portobello, shiitake and button), sliced
• 1½ cups heavy cream
• fresh thyme leaves for garnish (optional)