Grind the stuffed cookies and the hazelnuts in a blender. Add the lukewarm butter and mix.
Spread the mixture onto the mold, pressing well with a spoon to cover evenly the entire surface of the base.
Place the mold in the freezer until it is well cooled.
Melt the dumplings and the heavy cream in the bain-marie and stir until the mixture gets a smooth texture.
Pour the chocolate ganache into the mold and let it in the refrigerator to freeze and firm (about 8 hours).
For serving leave the cake out of the fridge for 15′. Dip a knife in hot water and use it to take off the cake from the mold.
Garnish with powdered coverture.