Slice 15 g chocolate into shavings and put aside. Roughly chop the remaining chocolate. Melt the chopped chocolate and butter in a pot. Heat 50 g whipped cream and dissolve coffee in it. Stir into the melted chocolate and let it cool down lukewarm.
Beat the egg whites until stiff, then add 30 g sugar. Carefully fold the beaten egg whites into the chocolate mixture. Divide into 4 glasses (each containing approx. 250 ml) and freeze for at least 3 hours.
Whip 100 g cream until semi-stiff, while pouring in 30 g sugar. Pour the cream onto the chocolate ice cream and decorate with chocolate shavings. Let the ice cream thaw for 3-5 minutes, then serve.