Soak gelatine in cold water. Coarsely chop the chocolate coating. Warm the cream in a pot, but do not boil. Melt the couverture in it slowly at low heat while stirring, as the couverture coagulates quickly.
Pour into a mixing bowl.
Beat egg whites until stiff. Squeeze out the gelatine and dissolve in a small pot at very low heat while stirring. Remove from heat. Stir 3-4 tablespoons of the couverture mixture into the gelatine by the spoonful. Then pour the gelatine mixture into the rest of the couverture mixture, stirring constantly.
Chill for 2-4 minutes until the mixture begins to gel.
Carefully fold in the beaten egg white with a whisk in 3 portions. Pour almost half of the mixture into eight glasses (each containing approx. 160 ml) and chill for approx. 3 hours.
Serve each glass of chocolate mousse with 1 cup of hot espresso. Pour the espresso onto the mousse at the table and enjoy immediately.