Despite the name ('candy'), there is nothing sweet about it: the 'caramel' is cheese melted onto the tortilla.
A flour tortilla is laid on the grill with cheese until it melts, then topped with mesquite-grilled carne asada, beans, guacamole and salsa at Hermosillo's carne asada taquerías.
Why it's made this way: It grew out of Hermosillo's carne asada taquerías, which took off from the late 1960s, and is regarded as a Sonoran taco, above all a Hermosillo one.