Finely chop the chocolate and place with the milk in the top of a double boiler over hot, but not simmering water, stirring frequently until smooth.
Separate the yolks from the whites and mix in with the chocolate.
Sprinkle in the icing sugar and stir well with a wooden spoon until soft peaks form.
While the melted chocolate is cooling down slightly (without hardening), whip the egg whites until they are foamy and beginning to hold shape. Sprinkle in a spoonful of sugar.
Fold in with the chocolate using a spatula.
Spoon the mousse into a serving bowl or individual dishes and refrigerate until ready to serve.
Decorate with whipped cream.
Ingredients for four
200 g dark chocolate
100 g icing sugar
Whipped cream for decoration
0.5 dl milk