Keens Steakhouse is known as the last bastion of the mutton chop, a dish that has fallen entirely out of favor in the rest of the city's chophouses. According to executive chef William Rodgers, who has helmed the kitchen at Keens for the last decade, it continues to be amongst the most popular menu items. However, the mutton chop served today is not your father's mutton chop. It might not even be mutton at all, but lamb.
Some things to consider: Modern lamb, like modern chicken and beef, grows much faster and much bigger than at any other time in history. This is a result of selective breeding and modern farming techniques, including finishing pasture reared animals on grain. Thus the size of a lamb loin in a year old animal today would have been difficult to achieve consistantly at a prior point in history. In the US sheep between the age of 12 and 16 months are considered "yearling mutton" and those above it mutton. According to Rodgers the animals Keens sources are "right on the cusp" of being a year old. But the chef really purchases his meat based on size — he is looking to serve a 26 ounce chop at a two inch height — not based on the age of the animal. Thus, Keens' claim that their chop is mutton rather than lamb is not as preposterous as some have claimed, though even the chef admits that he uses the term lamb and mutton somewhat interchangeably.
The chops are cut from whole loins that are pastured in Colorado. The meat is a darker red than that of most lamb you see on the market, betraying its age. But it is also well marbled, something that is rarer in younger lamb. All the meat at Keens is butchered in house and stored in the restaurant's cavernous dry aging room. While the lamb is not dry aged per se, since that process takes weeks, not days, it does pick up some subtle flavor notes from time in the meat locker. Rodgers is able to get three chops per loin, the left-over scraps are used to make the au jus that is served atop. While the saddle is treated relatively simply — it is seasoned with salt, seared in a 1000° broiler and brought to temperature in a 500° oven — the au jus that is ladled on top is far more laborious to produce. Lamb scraps are seared off in the pan to which the chef adds shallots, garlic, and veal stock. This is rendered down, infused with fresh mint, and strained, cooled and then reheated at service. A side of escarole sautéed in butter, lemon and garlic accompanies the saddle, the bitterness and acidy designed to cut the richness of the meat.
Take a look through the slideshow above to see how chef Rodgers brings this NYC classic to the table.