Gateau au Chocolat
 Melt chocolate in 3 T. water over low heat.  Add sugar, then butter. Remove from heat -- cool.  Then add yolks.  Then flour.  Beat egg whites until stiff.  Fold in chocolate.  Butter an 8" square or round pyrex dish. Pour batter in it.  Place pan in larger pan.  Fill larger pan with hot water to within 1" of top of cake pan.  Bake at 350  for 40 minutes.
   Melt chocolate over low heat with water.  Remove from heat.  Add butter. When cake is cool, unmold and pour glaze over it.  (you probably will have to spread it with a knife.)

 Keep in refrigerator until ready to serve.

 Decorate when cold using paper strips or a doily and 10x sugar.

 Can be doubled for a 9" x 13" pan.

May also substitute pareve margarine for the butter. For the powdered sugar, may combine caster (superfine) sugar with a little potato starch in a food processor or blender.