There are so many good things to eat in Mexico City that it seems churlish to complain about what's missing. But for the longest time one of the things I've longed for here is a decent piece of cheddar cheese. When I saw this at La Naval, at the corner of Michoacán and Insurgentes -- straight from los altos de Jalisco -- I was skeptical. What do they know about cheddar over there? But I thought, for 50 pesos, even if it's awful, I won't have lost much. And you know what? It's pretty good. It may not be some sublime English farmhouse concoction -- and it may not be precisely what you're thinking of when you think of cheddar -- but given that it comes from some mountain up in cowboy country, it will do okay.