Beef tenderloin cooks quickly and easily into a spectacularly tender roast. This long, cylindrical cut comes from the short loin – the most tender cut of the steer. Beef tenderloin has a mild, buttery flavor that makes it ideal for entertaining. Boneless, with little fat, it carves easily into lean but tender fillets, known as filet mignon. While you must cook most roasts at a low temperature so you don’t overcook the outer layers, this narrow roast cooks up tender even at a high temperature. Like other prime cuts, beef tenderloin is most tender when roasted to medium rare.
Remove the beef tenderloin from the refrigerator 60 to 75 minutes before you roast it. The roast cooks more quickly and evenly when first warmed to room temperature.
Preheat the oven to 425 degrees Fahrenheit. This is a high enough temperature to brown the outside and create a flavorful crust, without having to take an extra step to sear the roast.
Trim the tenderloin of extra fat. Peel off any skin that has not been removed by the butcher. Note that one end of the tenderloin is narrower. Fold this narrow end of the tenderloin into itself so the roast is uniform in shape and size. Wrap butcher’s twine around the roast at one-inch intervals.
Massage your favorite dry-rub spices into the roast to add flavor. Common spices include pepper, garlic, allspice and thyme. Hold off on the salt until after you’ve roasted the tenderloin in order to retain the flavorful juices.
Pat the entire outside surface of the tenderloin dry with paper towels. Do this just before you roast it to enhance the browning process.
Transfer the beef tenderloin to a rack placed in the middle of a shallow roasting pan. Place the pan, uncovered, in the middle of the oven.
Roast the tenderloin until an instant-read meat thermometer indicates an internal temperature of 135 degrees for medium rare or 145 degrees for medium. A two to three pound tenderloin will take 30 to 40 minutes to reach medium rare and 45 to 50 minutes to reach medium. A four to five pound beef tenderloin will take 50 to 60 minutes to reach medium rare and 60 to 70 minutes to reach medium.
Transfer the tenderloin to a serving dish, cover it with aluminum foil and let it rest for 15 to 20 minutes. The internal temperature continues to rise for a few minutes. After about 15 minutes, the meat relaxes and becomes more tender. The juices that have collected in the center of the tenderloin redistribute evenly throughout the roast.
Deglaze the pan, if you want to serve the tenderloin au jus. Stir in 1/4 to 1/2 cup of quality consommé or beef broth into the roasting pan. Scrape the pan drippings off the bottom of the pan as you bring the broth to a boil. Heat the liquid for several minutes to reduce it and concentrate the flavors.