For the most part, hamburgers in Mexico City disappoint. The accepted bread-to-beef ratio is shameful, with slender slices of overcooked meat hiding somewhere within the pillowy fluff of too much bread. The stringy, flavorless beef underwhelms. Even worse are the fancy sandwiches one finds at upscale burger joints, where blue cheese and spinach and a dozen other inappropriate ingredients only momentarily distract from the aforementioned defects of bad meat and a surfeit of bread. Against this dim backdrop of underachievement, the hamburgers at the Legión Americana shine like stars. This is something of a surprise considering the no-frills, dive bar atmosphere here.

In the past couple of years, in the fashionable neighborhoods of Mexico City, a panoply of high-class hamburger joints has opened. To delineate their distinction from anything to do with Mexico, most of them have names in English, and their menus offer burgers fashioned from ground sirloin, Kobe or Wagyu beef, with toppings as diverse as imported Stilton, caramelized onion and even foie gras. Their decoration is similarly varied, from sidewalk café to faux diner to intimate and candlelit. Perhaps predictably, at these emporiums the clients pay as much for a burger as they would in New York, Los Angeles or maybe even Tokyo.