In a large sauce pan bring water to a boil, with medium heat add butter, salt.
Add flour ALL AT ONCE stirring until a smooth ball forms, remove from heat and let stand 5 minutes.
Add eggs,1 at a time, beating well with each addition. Continue beating mixture until smooth and shiny.
Drop ¼ Cup full on to a well greased baking sheet.
Bake at 400º until golden, approximately 30-35 minutes. Move to a wire rack to cool cutting a slit into side of each to let steam escape. Cool completely before filling.
In a large bowl, beat together heavy cream, confectioners sugar, and vanilla until stiff.
Cut top off of pastry, remove excess dough from inside, fill puff, put top back on, sprinkle with confectioners sugar.