Cooking the Perfect Grassfed Beef Tenderloin

It is a holiday tradition at our house to cook whole beef tenderloin as a special occasion treat.  This cut is great to serve groups of friends and family that gather during the holidays and share this gift with them.  It tells them they are special to you. 

Beef tenderloin comes from the loin of a steer or heifer.  The tenderloin refers to the Psoas major muscle the runs along the central spine more or less between the shoulder blades and the hip socket.  Since this muscle does very little work in a quadruped it is the tenderest part of the animal. 

You can leave it whole or cut it into steaks.  When left whole the thick center can also be called Chateaubriand.    Created by his personal chef, Montmireil, for vicomte François-René de Châteaubriand, (1768–1848), the author and diplomat who served Napoleon as an ambassador and Louis XVII as Secretary of State for two years. This cut is usually only offered as a serving for two, as there is only enough meat in the center of the average fillet for two portions.

Whole tenderloins are often sold as PSMOs (pismos), which is short for peeled, silver skin, and side muscle left on. The PSMO is vacuum sealed in plastic, and can be safely refrigerated longer than many other cuts of meat. PSMOs also offer considerable savings over smaller cuts as they require little handling by the butcher, but obviously require more preparation on the part of the chef by doing the trimming.

Since it is the least stringy part of the animal, most beef dishes requiring high quality meat, such as steak tartare, are ideally made from the tenderloin.
So, if you invest in this most expensive cut of beef as a special treat you naturally want to be assured that it is prepared to perfection.  It does not take a chef to cook this cut perfectly and I will tell you how to do it.

The whole tenderloin in a grassfed animal is only 2.5 - 3 lb in size.  Like all beef it is best to have it at room temperature before you cook.  So, take the beef out of the refrig at least an hour before cooking. 

A whole tenderloin generally comes with one fat end and one skinny end.  If left like this it would cook unevenly and one end would be dried to a crisp while the fat end would not be done.  To eliminate this from being a problem I always fold the skinny end over on itself (trimmed of coarse) until both ends are approximately the same thickness.  I tie the roast at two-inch intervals with butcher string.  Not only does this keep the roast together where it is doubled but it keeps the entire roast from flattening out while cooking.  This gives you a more uniformly shaped roast and allows it to cook more evenly.
I always sear my tenderloin roast on top of the stove first to give a dark, caramelized crust before finishing it in the oven.  Pat the beef dry before searing.    Add kosher salt and fresh ground pepper to the outside before starting to sear.  I like to use a heavy cast iron skillet on medium high heat.  I usually do this in a dry skillet or if you like you can add a minimum amount of grapeseed or other high heat oil. Remember you are dealing with a round roast and this will require that you sear on all four sides to give an even crust.  You need a couple of minutes of undisturbed cooking on each side to form a proper crust so resist turning multiple times.
 
Once you have a nice dark and even crust remove the roast from the stove and while still in the pan finish by roasting in the oven.  I keep the oven temperature at 325.  Pay attention and when the roast reaches 120 degrees I remove it from the oven, tent with aluminum foil and let rest in a warm place for 15 minutes.  Since the beef continues to cook while resting the temperature will continue to rise another 10-15 degrees. This should give you a perfect medium-rare. The rest is very important as it allows for the internal juices to redistribute into the meat fibers rather than running out when you slice the roast causing the beef to dry out.

Slice your beautiful tenderloin roast into servings.  I like to do this at the table in front of my quests and serve their plates from the board.
Enjoy!