Prepare pâte à chou and fill a pastry bag with a large plain tube with the chou paste.
Pipe a half-inch-thick ring of chou paste around the edge of the pastry circle, one-quarter inch from the edge. With remaining paste make walnut-size puffs on another baking sheet. The gateau requires about eight of the puffs and the rest may be served separately. Brushpastry and the top of the puffs with dorure (egg wash), but do not let it drip down the sides.
Bake the pastry circle for ten to fifteen minutes, or until it is puffed and lightly browned. Pierce the inside edge of the cream-puff ring in four or five places with the point of a knife. Reduce oven heat to moderate (375°F.) and bake for ten to fifteen minutes longer, or until puff has dried. Cool on a wire rack.
Reheat the oven to 425°F. Bake the small puffs for ten minutes, or until puffed and lightly browned. Pierce each puff. Reduce heat to 375°F. and cook for about ten minutes longer, or until dried. Cool on a rack.