Beef Tenderloin with Wild Mushrooms

Ingredients

• 1 ounce dried porcini
• 1 whole beef tenderloin, 6 pounds, trimmed of all fat
• Kosher salt and freshly ground black pepper
• 2 tablespoons extra-virgin olive oil
• 1 clove garlic, crushed
• 2 pounds button or cultivated mushrooms, coarsely chopped
• 3/4 cup dry red wine, like Cabernet Sauvignon
• 1 cup beef stock
• 1 tablespoon unsalted butter