This recipe is from World War I, when sugar was in short supply. It was given to my mother by Babs Riffin of Montclair, New Jersey, who last year celebrated her 50th wedding anniversary. Mrs. Riffin’s mother made this cake during World War I, and Mrs. Riffin baked it herself during World War II, when sugar was scarce. There is neither cheese nor sugar in the recipe, but the applesauce and sweetened condensed milk combine with the eggs to give a cheesecake-l