Heat water and butter to boiling; reduce heat and stir in flour all at once. Stir about 1 minute until mixture forms ball around spoon. Remove from heat and beat in eggs, one at a time, until mixture is smooth. Place by rounded teaspoons-ful onto ungreased cookie sheets. Bake in a preheated 400ºF oven for about 25 minutes or until golden. Remove and cool on racks. Slice off tops; remove any doughy insides. Fill cavity with sandwich filling; chill until serving time. Makes about 25 puffs.