1.
Put the chocolate and 3 tablespoons of the water in a heavy-based saucepan.
2.
Heat gently, stirring until the chocolate has melted.
3.
Remove from the heat and stir in the brandy or liqueur. Whisk the egg yolks with the rest of the water until pale and frothy. Fold in the chocolate mixture.
4.
Whisk the egg whites until stiff and fold in. Spoon the mousse into individual serving dishes and chill well, preferably overnight.
5.
Serve decorated with whipped cream.