IN THE HEART OF MEXICO, where food is prepared with ingredients dating back to the Aztecs and the Spanish Conquistadors, exists the real tradition of Mexican cuisine. Often misrepresented, it is much more diverse than its watered-down cousin, Tex-Mex. Despite the cuisine’s broad variations from region to region, most Mexican restaurants in the U.S. barely skim the surface of the true depth of Mexican food. An ever-expanding Mexican population in the U.S. has sparked a growing pride in Mexican culture. Popularized by acclaimed chef Rick Bayless, contemporary Mexican food has found new recognition across the country, from small mom-and-pop shops to fine-dining urban establishments.