Adapted from bhg.com
Step 1: Shopping for tenderloin
The tenderloin comes from the loin, under the backbone and tucked between the rib and sirloin. Since this area doesn't get much of a workout, the meat is the most tender cut of beef available and is also the most expensive. Other benefits are that it is lean and boneless. Plan on four servings per pound. For a smaller roast, ask for a center-cut roast.
Step 2: Seasoning the meat
The trade-off for being so tender is that tenderloin can be a little less flavorful than the meat of more active muscles. Because of this, season it with a tasty stir-together rub. In a small bowl combine coarse-grain mustard, honey, black pepper, dry mustard, salt, orange peel, and lemon peel.
Step 3: Giving it a quick sear
Cooking the tenderloin in a hot skillet first quickly browns the meat. While this step is not essential, it caramelizes the outside while locking in all of the tasty juices. In a large skillet heat olive oil over medium-high heat. Quickly brown the tenderloin on all sides in the hot oil. Transfer the roast to a rack in a shallow roasting pan. Preheat the oven to 425 degrees F.
Step 4: Roasting until desired doneness Spread the mustard-spice rub over the top and sides of the tenderloin. Insert an oven-going thermometer into the center of the tenderloin. Roast in the preheated oven, uncovered, until desired doneness, according to the timings below. Transfer meat to a cutting board and cover with foil. Let stand for 15 minutes before slicing. The temperature of the meat will rise during this time (this is reflected in the timings below). Tip: If you don't have an oven-going thermometer, use an instant-read thermometer inserted into the thickest portion of the roast to test the temperature (do not keep this kind of thermometer in the roast during cooking). ut Weight Approximate Roasting Time (based on meat directly from refrigerator) Final Roasting Temperature (when to remove from oven) Tenderloin roast (cooked at 425°F) 1 pound 35 to 40 minutes 45 to 50 minutes 140°F (145°F medium rare after standing) 155°F (160°F medium after standing) 2 to 3 pounds 35 to 40 minutes 45 to 50 minutes 135°F (145°F medium rare after standing) 150°F (160°F medium after standing) 4 to 5 pounds 50 to 60 minutes 60 to 70 minutes 135°F (145°F medium rare after standing) 150°F (160°F medium after standing) Step 5: Serving After the standing time, cut the tenderloin into slices. The sliced meat will be juicy and flavorful as is, but if you prefer a sauce, consider pairing your beef with one of these: Mustard-Horseradish Sauce Bearnaise Sauce Bordelaise Sauce