Beef tenderloin is widely regarded as the tenderest cut of beef, and it's certainly the most expensive.
It's where we get high-end items like filet mignon, and it's a component of the ever popular T-bone and porterhouse steaks. It can also be roasted whole, or divided into smaller roasts.
What is the Beef Tenderloin?
The beef tenderloin is a long, narrow muscle called the psoas major, which comes from high up inside the beef loin, beneath the spine and directly behind the kidney. It extends roughly from the hip bone up to the 13th rib, and it doesn't get much exercise, which is why it's so tender.
It's encased in a thick layer of crumbly fat known as kidney fat or suet, which can be used in much the same way as lard.
A smaller, very skinny muscle called the psoas minor, commonly referred to as the chain, runs the length of the tenderloin and is often (but not always) removed before it gets to the meat case.
At the other end there's another muscle, the iliacus, sometimes called the side muscle or wing muscle.
Beef Tenderloin: To Remove Or Not?
The tenderloin is the key to the entire beef short loin. With each side of beef, a decision has to be made about whether to leave the tenderloin in or remove it.
For this reason, and also because it's so small (usually anywhere from 4 to 7 pounds), the tenderloin is a very expensive item.
If the tenderloin is removed, as it often is, the short loin can be fabricated into boneless top loin steaks, also known as strip steaks.
If the tenderloin is left in, the short loin can be fabricated into T-bone and porterhouse steaks. These are bone-in steaks with a section of strip loin on one side of the bone and a section of tenderloin on the other side.
Producing T-bone and porterhouse steaks means a portion of the tenderloin will remain in the sirloin. This rear part of the tenderloin called the butt tender, can be extracted, trimmed, and sold as a roast, or portioned into individual steaks.
Using the Beef Tenderloin
The tenderloin is actually shaped rather like a pencil, with a fat end at the rear (the sirloin end) and a pointy end facing forward.
This pointy tip can be a challenge to utilize since its shape doesn't lend itself to being made into a steak; but left attached to the roast, it can easily overcook. Therefore, when roasting a whole tenderloin, the tip is usually folded over and tied to the main body of the roast.
The tenderloin tip can also be removed and used for making seared beef hors d'oeuvres, or even kabobs or stir-fry meat. This is a very expensive stir fry. Still, there's not much else that can be done with a tiny, skinny piece of meat.
Moving further down, as the tenderloin widens, we can make tenderloin medallions, and then further down is where we get filet mignon.
Filet mignon literally means tiny filet, which means that a true filet mignon is made from the narrower end of the tenderloin. However, these days butchers will sell any steak from the tenderloin as filet mignon, even if it's from the butt end.
Butt tender steaks are sometimes tied up with butchers twine, to hold the wing muscle and the tenderloin muscle together. (The presence of string is thus a good indicator that a steak is not a true filet mignon.)
Another common technique for dealing with the skinny part of the tenderloin is to cut a longer section, say two inches long, and then butterfly it, which effectively produces a wider steak that's about an inch thick.
Beef Tenderloin: Tender and Lean
The tenderloin is a tender muscle, but also a very lean one, with comparatively little intramuscular fat, also known as marbling. And marbling happens to be one of the major factors in making a cut of beef moist and flavorful.
Thus, beef tenderloin can be prone to drying out if overcooked. Moreover, despite its popularity, it's not known as a particularly flavorful cut of beef, which is why you'll often see a tenderloin steak prepared with a strip of bacon wrapped around it. The bacon adds flavor and moisture to a steak that otherwise might not have enough of either.
One might rightly question whether a piece of meat that sells for $25 a pound should need to have a piece of bacon wrapped around it for it to taste good.
Still, tenderness is a characteristic that is highly prized, and butchers and restaurants are able to charge a very high price for beef tenderloin on that basis alone.
Cooking the Beef Tenderloin
For that reason, it's critically important that the tenderloin not is overcooked. Simply put, if a piece of meat is expensive because it happens to be extremely tender, the last thing you want to do is cook all its tenderness away.
As far as seasonings, high-end steaks generally don't need much more than Kosher salt and freshly ground black pepper. But because beef tenderloin is so lean, it can actually benefit from a quick bath in a flavorful marinade.