In Mexico, sandwiches generally come in the form of the torta, usually made out of a white bread roll known as a bolillo that has been sliced in half and then filled to the brim with meat, avocado, tomato, onion and sliced jalapeño peppers. In Mexico City’s San Rafael neighborhood, however, a family-owned sandwich shop called La Vaca de Muchos Colores is doing its best to expand the city’s sandwich scene.