Combine water and butter in a large heavy saucepan; bring to a boil. Remove from heat; stir until butter melts.
Add flour and salt; mix thoroughly until dough comes away from sides of saucepan. Add eggs one at a time, beating well after each.
Place dough in a pastry bag fitted with a large plain tip (or use a large spoon). Form 8 rounds on parchment paper-lined baking sheets; smooth tops with a finger dipped in cold water.
Bake at 400 degrees for 30 to 35 minutes, until golden. Let stand for several minutes in oven with oven door open; cool on a wire rack.
For Cream Filling: In a medium bowl, beat pudding mix and milk together with an electric mixer on medium-high speed; set aside. In a separate bowl, beat whipping cream until soft peaks form. Gently fold whipped cream into pudding mixture. Chill. Slice puffs open; fill with Cream Filling. Garnish as desired with a sprinkle of powdered sugar or a drizzle of melted chocolate. Serve within one hour. Makes 8 puffs.