Dust 9x13 glass baking dish with powdered sugar.  In a small bowl, soak gelatin with 1/2 cup of the cold water and set aside.  In a medium saucepan, cook sugar in the other 1/2 cup water until sugar dissolves.  Add gelatin mix and bring to a boil.  Pour into large mixing bowl and allow to partially cool.  Add salt and vanilla and beat with electric mixer until soft and doubled in size.  Pour into pan and dust top with more powdered sugar.  Set to cool until it is no longer sticky (a few hours).  Cut and roll in powdered sugar.