Heat oven to 400. Bring water to boil in a heavy pan. Reduce to low heat. Add b utter, salt and flour all at once. Cook, stirring vigorously until mixture leav es sides of the pan and forms compact ball. Remove from heat. Cool slightly. Ad d eggs, one at a time, beating after each addition until smooth and glossy.
Drop on ungreased cookie sheets by teaspoon or tablespoon, depending on size de sired. Bake 30 minutes for miniatures, 45 minutes for larger ones. When cooled, cut off tops and fill. The puffs may also be frozen unfilled, refreshed in the oven and then filled.
Makes 12 large or 50 to 60 miniature puffs.