A Pittsburgh rare steak is one that has been heated to a very high temperature very quickly, so it is charred on the outside but still rare or raw on the inside. The degree of rareness and the amount of charring on the outside may vary according to taste. The term 'Pittsburgh rare' is used in some parts of the American midwest and eastern seaboard, but similar methods of sear cooking are known by different terms elsewhere, including Chicago-style rare and, in Pittsburgh itself, black and blue.
A Pittsburgh rare steak may be prepared using a very hot grill, griddle, frying pan, or oven. The high temperature allows the steak to char in a short enough time that the inside remains uncooked.
One story relates that the method originated as an explanation for an accidental charring of a steak at a Pittsburgh restaurant, with the cook explaining that this was "Pittsburgh style."[1]
It has been said that the 'original' method of preparation was by searing the meat with a welding torch. Whether this is true is unknown, in any case, it is difficult to attain high enough temperature with a common blowtorch. Another method, related by a staff member at a Pittsburgh branch of Ruth's Chris Steak House, originates from the region's steel mills, and the practice of workers cooking a steak on a cooling piece of steel. The temperature of the steel would be such that it would be impossible to do more than char the outside of the steak while keeping anything worth eating. Whether either of these origins is genuine or just a play on Pittsburgh's industrial image is debatable.