The porterhouse is a composite steak coming from the point where the tenderloin and top loin meet. It is basically an over-sized T-bone steak, but the porterhouse is generally cut thicker and has much more of the tenderloin relative to the loin portion than a T-bone steak. If you remove the bone and cut out the two steaks that make up the porterhouse, you will get a tenderloin steak and a top loin (or New York strip steak). That means if you are ordering a porterhouse, expect big portions! A good porterhouse is also the perfect steak for two people to share.
Buying a Porterhouse
When buying a porterhouse steak, look for one cut at least 3/4-inch thick, with a 1-inch thickness being ideal. Occasionally, butchers will sell "thin" cut steaks, and these are largely pointless. A porterhouse should be thick, and not just because it is a huge steak and deserves to be so. In order to get a large steak like this cooked to perfection without it drying out, it needs to have significant mass and thickness.
A good porterhouse should have a deep, rich color without any gray. The fat should be white and not yellow. Look for good marbling throughout the meat, particularly the loin portion. Don't try to get a bargain on a steak like this. While dry-aged and/or prime grade versions of the porterhouse will be expensive, you can find a good "choice" grade steak that is fresh and very flavorful.
Cooking a Porterhouse
Since both the loin and tenderloin are quite forgiving, a porterhouse steak can be cooked any way you like. It is perfect when grilled, but can also be broiled, sautéed, or pan-fried. Use light seasoning with a good amount of salt and try not to cook it beyond medium-well at the very most.
To grill a porterhouse, start hot and fast, giving the surface a good sear. Cook to the point right before the fat would start to burn, then flip it over on the other side. To get those restaurant-style diamond grill marks, rotate it 45 degrees on the same side before flipping and repeating on the other side.
Once it is well-browned on both sides, move it to a cooler part of the grill to finish off to the desired doneness. To give it an extra richness, place a pad of butter in the center of the steak a few minutes before removing from the grill. This is a popular restaurant trick that brings out the flavor.
One way to grill porterhouse is as a cowboy steak. Give it a southwestern twist by seasoning it with a paste that includes garlic, chili powder, chipotle powder, salt, and pepper. Make sure to wrap it in plastic and refrigerate it for a few hours so it absorbs the spices before grilling.
Serving a Porterhouse Steak
A porterhouse can be served whole or sliced, depending on how you want to divide it up. For the very hearty appetite, it is a tremendous meal—even a challenge! As a steak for two, this makes the perfect steak to indulge in on particularly special occasions.