There’s nothing sacred or cultural about serving two tortillas with tacos. It’s mostly a practicality to keep moist fillings from causing the tortillas to fall apart. In fact, at many Mexican street stalls, the vendors will ask if you want one tortilla or two. Local taquerias may use two to ensure that thin, factory-produced tortillas can stand up to their contents, but it is mainly the decision of the cook.
The smooth, chewy tortillas popular at chain restaurants may seem a sacrilege to lovers of truly authentic Mexican food. But they are essential to the cuisine of many Northern Mexican states and form the basis of American Tex-Mex dishes.
Ranging from a deep, earthy brown to pale white, these “little cakes” have been a staple in Mexican and Central American cultures since well before Christopher Columbus arrived in the New World. The recipe originally derived from the abundance of local corn crops in areas where farmers did not produce wheat. The same masa harina base for flat taco wrappers can be used for thicker preparations, such as sopes and chalupas.