Let a springform pan (approx. 20 cm Ø) cool in the refrigerator for at least 2 hours. Heat the cream and remove from the stove. Break the chocolate into pieces and melt in it while stirring. Stir in cinnamon. Pour into the pre-cooled springform pan and chill for at least 4 hours.
Drain the cherries in a sieve, collecting the juice. Stir 4 tbsp. juice and sauce powder until smooth. Boil up the rest of the cherry juice in a pot. Stir in the sauce powder and sugar. Simmer for 1-2 minutes, remove from the heat and season with grappa. Let it cool down and put it in a cool place. Mix crème fraîche with milk. Dust the Gateau with cocoa, remove from the springform pan and cut into pieces.
Stir in the sauce powder and sugar. Simmer for 1-2 minutes, remove from the heat and season with grappa. Let it cool down and put it in a cool place. Mix crème fraîche with milk. Dust the Gateau with cocoa, remove from the springform pan and cut into pieces. Serve with cherry compote and crème fraîche
waiting time approx. 6 hours