When patrons of fine steakhouses want the best cut of beef on the menu, the waiter will often suggest a large T-bone known as a Porterhouse steak. This steak is quite often the thickest and largest cut offered on most traditional steakhouse menus, with the possible exception of prime rib. Consequently, it may also be among the most expensive entrees as well.
A butcher creates both T-bone and Porterhouse steaks from the same area of the cow, the short loin and tenderloin region just behind the upper rib section. Slicing through the cow's vertebrae creates a T-shaped bone. This bone separates two sections of meat, the larger short loin section and the smaller but prized tenderloin section. A traditional T-bone steak can be sliced fairly thin, and may not contain very much tenderloin at all, depending on its location along the spine, but a Porterhouse must be cut much thicker in order to be sold under this name.
The tenderloin section of a cow is essentially a wedge that grows bigger towards the back of the cow. Cuts made along the back section of the short loin will have much larger portions of tenderloin, and this is the area butchers carve to create true Porterhouse steaks. A typical cow might yield a number of thinner T-bone steaks, but only a few thick cuts which would pass the legal definition of a Porterhouse. Some restaurants or meat producers may try to label regular T-bones with this name, but this practice is considered deceptive.
A Porterhouse steak is ideal for grilling or broiling because it does not contain much collagen that needs to be cooked off slowly. Because the two sections of the steak cook at slightly different temperatures, it is not unusual for a finished steak to reach two different states of doneness. Cooks must learn how to control or manipulate their grills or broilers in order for both the tenderloin and the short loin sections to reach the same level of doneness desired by the customer. Because the number of Porterhouse cuts may be limited, many steakhouses leave the responsibility of preparing one to their most experienced cooks.