Strip steaks are usually boneless, but the bone-in version is sometimes called a shell steak or club steak. The bone adds flavor and moisture, in addition to making it more impressive-looking, which is why you often see them served in restaurants.
Differences Between Strip Steaks and Other Cuts
If you left the tenderloin in, you'd have T-bone and porterhouse steaks, rather than strip steaks.
The bone in question is the backbone (specifically the thoracic vertebrae), which is usually removed to produce a boneless strip loin. But it's the muscle in the meat that determines how flavorful and palatable a steak will be.
Muscles in Strip Steaks
The primary muscle in the strip loin is the longissimus dorsi, which also happens to be the main muscle in a rib eye steak. It actually extends from the hip bone up all the way up to the shoulder blade, and it's a very tender muscle.
Since they're generally a single muscle, strip steaks don't have much connective tissue or fat, both of which are mainly found in between muscles.
What they do have is a good amount of intramuscular fat, or marbling, which adds flavor and moisture to a steak.
In fact, the degree of marbling is one of the main characteristics used to assign quality grades to meat. More marbling means higher quality.
Having said that, there are two other muscles that might appear in a strip steak: the multifidus dorsi and the gluteus medius.
The multifidus is a tender muscle, and if it's present, it will be up at the top (the wide end) of the strip steak. It's sometimes trimmed off the strip loin, but it's OK if it's not.
The gluteus medius, on the other hand, is not a muscle you want to see in your strip steak.
The gluteus is the sirloin muscle, and you'll only see it in the last (or maybe the last two) strip steaks, at the very end of the short loin. Not only is the gluteus muscle tougher than the strip loin, but the vein is going to be quite chewy.
Cooking Strip Steaks
Strip steaks are easy to cook on the grill, under the broiler, or on a cast-iron skillet. By comparison, consider porterhouse steaks, which are made up of a strip steak and a tenderloin steak, each with its own cooking time.
That makes cooking a porterhouse to a uniform degree of doneness nearly impossible. But strip steaks are easy to cook and don't need a lot of fussy preparation to taste great.
Choosing a Strip Steak: What to Look For
If buying strip steaks from a butcher, the ones you want are from the rib end or the center of the strip loin. And it's easy to tell the difference by looking at the shape of the steak.
Look for steaks that are wide and relatively straight, with not much difference in width from top to bottom. The fat around the edge should be trimmed to about 1/8 of an inch all the way around.
Avoid steaks that are kind of wavy, or shaped sort of like a question mark, or have one end that is substantially narrower than the other. These are from closer to the sirloin end and less desirable.
Indeed, you might even see something called a "center-cut" strip steak, which sounds like it must be from the center. But all it means is that it can't be the last one from the sirloin end.
The worst you can get with a center-cut strip steak is one that has a small piece of the gluteus medius, but it won't be visible on both sides of the steak.