Combine butter and salt with water in a heavy-saucepan and bring to a boil, When butter is melted, add flour all at once, beating vigorously over medium heat until dough forms a ball and leaves the side of the pan.
Remove from heat and beat in eggs, one at a time, waiting until each egg is absorbed before adding next.
Place dough in a pastry bag fitted with a medium plain tube and squeeze 3/4 inch mounds onto a greased baking sheet.
Bake in a preheated 425Â° oven 15 minutes; reduce heat to 350Â° and bake 10 to 15 minutes longer or until browned and dry.
Cool puffs on cake racks.
Cut off top third of each puff.
Fill as desired and replace tops.