enchilada (n.)

Mexican dish made with chili sauce, 1876, American English, from Mexican Spanish enchilada, fem. past participle of enchilar "season with chili," from en- "in" + chile "chili" (see chili). Recorded by 1861 as tortillas enchiladas.

You never ate enchilada, did you? I hope you never will. [...] An enchilada looks not unlike an ordinary flannel cake rolled on itself and covered with molasses. The ingredients which go to make it up are pepper, lye-hominy, pepper, onions chopped fine, pepper, grated cheese, and pepper. [The Health Reformer, December 1876]

The 1876 description later adds that the lye-hominy is for the tortilla batter. Rolled enchiladas are more common in Mexico but a style of layered enchilada is common in New Mexico.

First a tortilla in the center of a plate. Then a flood of rich red chile sauce from a near-by kettle, a layer of grated cheese, another tortilla, more chile and more cheese sprinkled between in layer cake fashion, and the whole topped with a high crown of chopped onions in which nestles an egg, which has been broken for a minute into the hot lard. An artistic and cooling garnish of lettuce, and behold an enchilada. [Louise Lloyd Lowber, "A New Mexico Supper at the Famous Enchilada House in Old Albuquerque." American Cookery, Oct. 1921.]

The saying the whole enchilada to mean "everything" is attested by 1965.