Note: If you want to work ahead, the sauce will keep for several days in the refrigerator, well covered, though you may notice the garlic flavor becoming a little stronger. If the sauce has thickened to more than the consistency of canned tomato sauce, thin it with a little water before using. Once you start frying the enchiladas, though, the short fuse to dinnertime has been lit—these can survive for only 30 minutes before the final 5-minute warming.
