Preheat the oven at 180°C (350°F).
Make the vegan egg by combining 2 tbsp of ground flax seeds with 6 tbsp of water, and set aside (alternatively you can use 1/2 cup of applesauce and add with the liquids).
Stir the apple cider vinegar into the soy milk and set aside.
In a large bowl weight all the dry ingredients: flour, sugar, cocoa, baking powder, baking soda and salt.
Make a hole in the middle and add the vegetable oil, the egg replacement, the vanilla, the cherry syrup (or booze) and the vegan buttermilk, and give a little stir.
Bring the water to a boil, and add to the cake mixture. Whisk vigorously to a smooth batter.
Add the optional dark chocolate chips now, and combine into the batter.
Line three-8inch round hinged moulds with baking paper, and pour into each one 1/3 of the batter*.
Bake for 40 minutes or until the wooden skewer comes out dry from the cake. Once cooked, allow to cool completely at room temperature.
For the chocolate barks: melt** 2/3 of the chocolate (finely chopped). Remove from heat and stir in with a spatula the remaining 1/3 until it's all well melted and smooth.
Line one large piece of parchment paper on your working surface. Pour over the melted chocolate and spread it with a spatula into a thin (2-3 mm) layer***. Roll up from the short side of the parchment, and place in the fridge or freezer until firm.
Add the vegan whipping cream and the powdered sugar to a bowl, and whisk it into stiff peaks.
Place the first disk of chocolate sponge on the bottom, spread over around 2/3 of the vegan whipped cream and half of the preserved black cherries cut in halves.
Repeat for another layer.
Top the cake with the last disk of chocolate sponge, and coat both the top and sides with a thin layer of cream.
Decorate the top by piping some whipped cream kisses around the cake and the sides with the tempered chocolate barks.
Finish with (literally!) the cherry on the cake, by placing the fresh cherries in the center of the cake.
Refrigerate the cake for at least 2 hours before serving (better if overnight).