Into a small saucepan put the water with the butter and sugar. When boiling add gradually the flour and stir till the mixture is stiff. Take from the fire, stir some more, then add the eggs, one at a time, beat the whole well, and leave to cool. Butter a baking sheet, lay the paste on it in round balls the size of a plum and bake in a moderate oven for about twenty minutes. Allow to cool and then make an incision in the side of each and fill with whipped cream slightly flavored with vanilla or with jam. Just before serving glaze each chou slightly with a chocolate icing.