Ingredients

• 2 ounces dried porcini mushrooms
• 2 cups boiling water
• 1/4 cup (1/2 stick) unsalted butter
• 1 large shallot, chopped (about 1/2 cup)
• 3 large garlic cloves, chopped
• 1/2 pound fresh crimini (baby bella) mushrooms, stemmed, caps sliced
• 1/2 pound fresh shiitake mushrooms, stemmed, caps sliced
• 1 teaspoon chopped fresh thyme
• 1 teaspoon chopped fresh sage
• 1 cup dry vermouth or dry white wine
• 4 1/4 cups Ultimate Turkey Stock or low-salt chicken broth, divided
• 1/2 cup crème fraîche
• 5 teaspoons cornstarch
• 1 1/2 teaspoons chopped fresh tarragon
• ingredient info: Dried porcini and crème fraîche are available at many supermarkets and at specialty foods stores.

Instructions

1. Place dried porcini in large bowl. Pour 2 cups boiling water over. Let stand until soft, stirring occasionally, about 1 hour. Using slotted spoon, transfer porcini to small bowl. Cool porcini, then chop. Pour porcini soaking liquid into medium bowl, leaving sediment behind.
2. Melt butter in large skillet over medium-high heat. Add shallot and garlic. Stir 15 seconds. Add fresh mushrooms, thyme, and sage. Sauté until mushrooms are tender, 6 to 7 minutes. Transfer mushrooms to bowl. Add vermouth to skillet; boil 3 minutes, scraping up browned bits. Add 4 cups stock, fresh-mushroom mixture, porcini, and porcini liquid. Boil 10 minutes.
3. Whisk in crème fraîche. Stir 1/4 cup stock and cornstarch in bowl to dissolve; mix into gravy. Cook until gravy coats spoon, about 5 minutes. Season with salt and pepper. DO AHEAD: Can be made 1 day ahead. Cool, cover, and chill. Rewarm before continuing.
4. Whisk tarragon into gravy and serve.