A portmanteau of "enchilada" and "lasagna", it refers to a hybrid of the two dishes. In this dish, tortillas, refried beans, meat, cheese and other enchilada ingredients are layered in a pan and baked, in the the fashion of lasagna.
PERSON 1: So I made enchilagna last night, and it was tasty.
PERSON 2: That sounds good.
PERSON 1: It was.