In a large bowl with a balloon whisk (or in the bowl of a mixer fitted with the whisk attachment), whip the cream to soft peaks. Add the icing sugar and vanilla, and continue whipping to firm peaks. Set aside in the fridge until you are ready to use it.
For the soaking syrup
In a medium saucepan, combine the sugar and water. Heat the mixture over medium-high heat until the sugar is completely dissolved and the syrup comes just to the boil. Remove the pan from the heat and set it aside to cool.
When the syrup has cooled, add the kirsch to flavor it. Set aside.
To assemble the cake
Place the first layer of cake on a cake board (or a rotating cake stand like this one on Amazon) and brush generously with the soaking syrup (if working with a génoise cake, brush on enough syrup that when you press on the cake, the syrup comes up).
Top with a layer of whipped cream and a third of the cherries. Press the cherries in place lightly, then spread another thin layer of whipped cream over top to lock them in place.
Repeat steps 1 and 2 with the the second layer of cake.
Top the cake with the third layer, brushing it with syrup and topping it with a thin layer of whipped cream.
Spread whipped cream on the sides of the cake and smooth the surface.
Press chocolate shavings all over the sides.
Top the cake with more chocolate shavings and pipe on a few decorative rosettes with a star tip. Place a cherry in the middle of each rosette.
Sprinkle the cake with a little cocoa powder and icing sugar before serving.
For this recipe, you can buy boozy cherries like these on Amazon