Chop the chocolate and melt over a hot bain-marie.
Soak the gelatine in cold water.
Separate the eggs. Put the egg yolks, sugar and 1 egg white into a beating bowl with the coffee liqueur and beat over a hot bain-marie until pale, thick and foamy (do not let it get too hot!).
Remove from the heat and stir in the squeezed out gelatine and the chocolate.
Whip the cream until stiff and fold in.
Whip the egg whites until they form stiff peaks and fold in also.
Divide the mixture between two bowls.
Fold the espresso and cocoa powder into one half.
Divide this half between four six (approximately 8 cm in diameter and 6 cm high) and smooth the top.
Leave to set.
Crumble the amarettini and meringues and scatter on top of the mousse.
Now divide the light mousse between the glasses and smooth the top.
Chill for at least 2 hours.
Before serving remove the rings and decorate with hazelnuts, gianduja and chocolate-coated coffee beans.