150 g dark chocolate, preferably 65% cocoa, 1 egg + 4 yolks, 80 g sugar, 280 ml single cream
Melt the chocolate in a mixing bowl over a saucepan of simmering water until smooth. Leave to cool.
Mix the egg, yolks, and sugar. Place the preparation in a mixing bowl over a saucepan of simmering water, and cook, stirring continuously until a very light mousse, tripled in volume, is produced.
Incorporate the melted chocolate off the heat. Mix gently and leave to cool. Whip the cream. Then incorporate it into the chocolate using a spatula. Refrigerate for 1 to 1 ½ hours.