8ouncesfresh mushrooms, sliced (we used oyster mushrooms)
1large shallot, finely chopped
1clovegarlic, finely chopped
Salt and freshly ground black pepper
Remove the tenderloin from the refrigerator and set aside for 30 minutes to remove the chill. Coat a roasting pan and rack with nonstick spray.
Combine the pepper, salt, garlic and olive oil in a small bowl to form a paste. Place the tenderloin on the roasting rack and coat the top and sides with the seasoning paste. Set aside for another 30 minutes to come to room temperature.
Meanwhile, reconstitute the dried mushrooms by warming the beef broth in a microwave-safe bowl for 2-1/2 to 3 minutes on high. Stir in the mushrooms and set aside for 30 minutes. Once the mushrooms have rehydrated, strain the liquid into a separate bowl and, if necessary, cut them into bite-sized pieces.
Preheat the oven to 400°F.
To continue with the sauce, melt the butter in a saucepan over medium heat. Add the shallots and garlic and sauté until fragrant, 2 minutes. Add the flour and continue cooking until the mixture turns pale golden in color, 3 to 4 minutes more. Transfer to a bowl and set aside.
Add the port to the saucepan, increase the heat to medium-high and bring to boil. Cook for 5 minutes, then add the reserved mushroom liquid and bring to a rapid simmer. Stir in the shallot-flour mixture and continue cooking, stirring constantly, until the sauce starts to thicken, about 3 minutes. Add the Worcestershire, fresh and dried mushrooms and cook until the sauce reaches a thick, chunky consistency. Season to taste with salt and pepper and keep warm until ready to serve.
Roast the tenderloin until an instant-read thermometer registers 120°F for rare or 125 to 130°F for medium rare. Begin checking the temperature after 18 minutes. Once the meat is done, tent with foil and allow it to rest for 15 minutes before carving.
Cut into 1/2-inch thick slices and serve with the mushroom sauce.
Tips for Making This Recipe
Ask your butcher for the center portion of the beef tenderloin (sometimes labeled Châteaubriand) and get him to trim the silver skin for you. You'll need between 6 and 8 ounces of meat for each guest, so if you're feeding more than six, we'd suggest buying multiple roasts of equal size to keep the diameter of the roast consistent (whole beef tenderloins taper toward the ends).
About the pepper crust:
We used a combination of freshly ground black, green and pink peppercorns for our seasoning crust ~ a total of about 3 teaspoons. Because the green and pink varieties tend to be a little less pungent than black, the resulting crust was distinctive and flavorful, but not intense enough to overpower the flavor of the meat or the mushroom-port sauce. Use your judgement as to how much pepper you like and what varieties to use.