Brown beef and onion, drain. Sprinkle meat with 1/4 tsp
                           salt  and a dash of  pepper. Split chiles lengthwise and remove
                           seeds, spread open.  Lay half of  the chiles on the bottom of a
                           shallow 1 qt baking dish.  Sprinkle with cheese and top with meat
                           mixture. Arrange remaining chiles over the meat.
                           Gradually add  milk to the flour, stirring until smooth.  Add salt,
                           pepper, eggs and hot pepper sauce. Beat until smooth.  Pour
                           over the casserole.
                           Bake at 350 degrees for 45 to 50 minutes (knife inserted just off
                           the center comes out clean).  Pour off excess fat and cool 5
                           minutes before  serving.