Put dark sweet cherries and cherry syrup into blender and puree it.
Boil sugar, cherries puree and gelatine powder together. Leave to cool.
Fold in whipped fresh cream and kirsch liqueur to the cherries puree.
And spread mousse on cake and place dark sweet cherries on it and cover with 2nd piece of cake, then spread the balance on top. Leave the mousse cake to set in refrigerator for few hours to set.
Cherries syrup