Cook the ground beef, onions, and garlic, stirring frequently to break up beef, until onions are clear. Remove excess fat rendered from beef. Stir in the chiles and salt.
The Sauce: In a blender or food processor, puree together the soup, chiles. onion, garlic, broth, masa harina, and spinach. More than one batch if necessary. Pour puree into a sauce pan and bring to boil. Reduce geat,and cook, stirring until thickened and bubble. Add salt and adjust seasoning. To Build: In a greased 13 X 9 X 5 cm baking dish, arrange half the tortillas over the bottom. Top with half the beef mixture. Repeat layers. Pour green chile sauce over beef. Top with shredded cheese. Bake at 325� for 50-55 minutes.