Things You'll Need
Beef tenderloin, 5 lbs.
Desired seasoning or marinade
Located on either side of the vertebrae, the beef tenderloin is a long, narrow cut of beef that is considered to be very tender. This long strip of beef is ideal to roast and then slice into portions for serving. A relatively lean cut of beef, one 3-oz. serving has 156 calories, 6 grams of fat and 30 grams of protein. While you may apply different marinades or sauces to the beef tenderloin before cooking, the roasting process for a 5-lb. beef tenderloin is generally the same.
Preheat the oven to 400 degrees F.
Trim and discard any excess fat on the outside of the beef tenderloin with your butcher's knife. This is an optional step; some people prefer to get the tenderloin as lean as possible, while others want to use the fat to baste the beef while cooking.
Season your beef tenderloin. Refer to your recipe for instructions. A simple seasoning for a 5-lb. beef tenderloin includes rubbing the exterior with a small amount of olive oil. Next, lightly dust the exterior of the beef with freshly cracked salt and pepper.
Place the beef tenderloin fat-side up on your roasting rack. This will allow the fat to help baste the meat during the cooking process as it melts. Place the roasting rack inside the roasting pan.
Place the beef tenderloin in the oven for 45 minutes. After 45 minutes, check the temperature with your meat thermometer. A temperature of 140 degrees F is rare, 145 degrees F is medium-rare, 160 degrees F is medium, 165 degrees F is medium-well and well-done is 170 degrees F and beyond. Remember that your meat will continue to cook for several minutes after it has been removed from the oven. Therefore, pull it from the oven 5 to 10 degrees below your desired level of doneness. Check the internal temperature with your meat thermometer one final time before slicing.
Allow the meat to rest for 5 to 10 minutes before slicing. This allows the meat to retain all the juices. If you cut the tenderloin prematurely, the juices will run all over the cutting board. This may cause the tenderloin to be dry by the time it is served.
A pork tenderloin can be roasted in the same manner. According to the USDA, pork must be cooked to an internal temperature of 145 degrees F. This will result in the meat still being slightly pink. People who prefer pork well-done should cook the tenderloin until it reaches an internal temperature of 165 degrees F.