Start to finish: 2 hours (1 hour active)
Servings: 8 to 10
its flavor is quite mild, we use a trio of bold ingredients—mushrooms, rosemary and black
pepper—to bring depth and savoriness. We create a seasoning rub by finely grinding umami-
packed dried porcini mushrooms (shiitakes work, too), rosemary and pepper, and we roast the
meat over a layer of fresh portobello mushrooms and sliced onion. The mushroom-onion
mixture becomes a rich, flavorful accompaniment to the meat. Because portobellos contain a lot
of water, we give them a head start on cooking and add the tenderloin to the pan only after they
begin to brown. You will need a large roasting pan—one that measures about 12 by 15 inches—
along with a V-style roasting rack.
Don’t skip the step of scraping the gills off the portobello mushrooms. Though edible, the gills
turn the roasted mushroom-onion mixture a murky brown. Simply use a spoon to scrape off the
gills on the underside of the caps before halving and slicing them. Also, make sure to allow the
roast to rest before slicing. This allows the juices to redistribute throughout the meat so they
don’t all flow out onto the cutting board when the meat is carved.
¼ ounce dried porcini mushrooms or dried shiitake mushroom caps (about 8 small caps),
broken into pieces
2 tablespoons fresh rosemary
Kosher salt and ground black pepper
1 tablespoon black peppercorns
4- to 5-pound beef tenderloin roast, trimmed of fat and silver skin
6 tablespoons extra-virgin olive oil, divided
1½ pounds portobello mushroom caps, gills scraped off with a spoon, halved and sliced ¼ inch
thick
1 medium sweet onion or yellow onion, halved and sliced ¼ inch thick
1 tablespoon sherry vinegar
1 cup lightly packed fresh flat-leaf parsley, roughly chopped
Flaky salt, to serve (optional)
Working in batches, use a spice grinder to pulverize the porcini to a fine powder, then transfer it
to a small bowl. Repeat with the rosemary and 2½ teaspoons kosher salt, pulverizing until finely
ground and adding it to the mushroom powder. Repeat with the peppercorns. Stir the
seasonings, then measure 1 tablespoon into another small bowl and set aside. Sprinkle the
remaining mix all over the tenderloin, rubbing it in.
Tuck the tapered end of the tenderloin under itself so the roast is of an even thickness. Using
kitchen twine, tie the tenderloin at 1-inch intervals, making sure the tucked portion is secured
with the twine. Brush the roast all over with 3 tablespoons of the oil, place on a V-style roasting
rack and set aside at room temperature until ready to roast.
Heat the oven to 450°F with a rack in the middle position. In a large (about 12 by 15 inches)
roasting pan, toss the portobello mushrooms, onion, remaining 3 tablespoons oil and ½
teaspoon each kosher salt and ground pepper. Roast for 15 minutes. Remove the pan from the
oven, stir the mushroom mixture and set the rack with the tenderloin in the pan. Roast until the
thickest part registers 120°F for rare or 125°F for medium-rare, 35 to 45 minutes.
Transfer the roast to a large platter and remove the rack from the pan. Tent the roast with foil
and let rest for 30 minutes. If there is liquid in the pan, before proceeding to the next step, stir the
mushroom mixture, return the pan to the oven and cook until the liquid has evaporated.
To the mushroom mixture, stir in half of the reserved seasoning mix, the vinegar and parsley.
Transfer the rested tenderloin to a cutting board. Remove the twine and carve into ½-inch slices.
Pour any juices on the platter and cutting board into the mushroom mixture, then taste the
mushrooms and season with kosher salt and pepper. Transfer the mushrooms to the platter,
then arrange the sliced tenderloin on top. Sprinkle with the remaining seasoning mix, along with
flaky salt (if using).