Inspired by the classic lamb stew known as "Birria, " This recipe slow-braises a tender leg of lamb for hours, then the leftover liquid is mixed with ancho and chipotle chiles along with cumin and cinnamon to form the base of a flavorful sauce. Steamed rice absorbs all of the delicious juices and a crunchy cabbage slaw tossed with lime juice offsets the lamb's earthy flavors. Add a scoop of sour cream to tame the heat and use soft tortillas to wipe up any tasty bits of leftovers.