Preheat your oven to 180°C (356°F). Line the base of two 8" cake tins with a circle of parchment paper and spray the sides with oil spray.
Add the plain flour, soft brown sugar, cocoa powder, baking powder, and sea salt to a large mixing bowl, whisk and set aside. To make the vegan "buttermilk" add the soy milk and apple cider vinegar to a jug, stir and allow to sit for 10 minutes.
Add the vegan buttermilk mixture, sunflower oil, vanilla extract, and hot coffee to the bowl with the dry ingredients and whisk carefully to combine. Do not overmix the batter.
Divide the batter into the lined cake pans and bake for 30-35 minutes. Check they are ready by inserting a skewer, it should come out clean. Allow the cakes to cool in the tins for 15-20 minutes and then carefully turn them out onto a cooling rack to cool further. Refrigerate the cakes in an airtight container until ready to use. Chilling the cakes for a few hours (or overnight) makes them easier to work with and decorate.
Defrost the cherries and reserve the liquid juice if using (see recipe notes below).
Add 50ml of the cherry juice to a saucepan with cornstarch and sugar and whisk until evenly mixed. Add in the remaining cherry juice and simmer over medium heat for 5 minutes, stirring frequently with a rubber spatula or whisk. The mixture will thicken.
Remove the cherry mixture from the heat and stir in the Kirschwasser. Allow the mixture to cool slightly for 10 minutes, then stir in the cherries. Cool for another 10 minutes until it reaches room temperature.
To make the chocolate curls, melt the chocolate and pour it into a small plastic container lined with parchment paper. Freeze for 20-30 minutes, then remove the block of chocolate from the container and use a potato peeler to create chocolate curls in long movements while applying pressure. I recommend wearing latex gloves for this step as the heat from your hands will melt the chocolate. If the chocolate gets too soft, return it to the freezer for 10 minutes and repeat.
Using a serrated knife, carefully cut the domes from the tops of the cakes if there are any to get them as even as possible. If desired, you can leave the dome on the top cake, just like I did in the pictures shown. Place a tiny amount of whipped cream on a cake turntable and secure the first sponge layer on top of it.
Using a pastry brush, coat the first cake layer with some syrup from the cherry filling. Use a piping bag or offset spatula to spread a layer of the vegan whipped cream, followed by a layer of cherry filling. Place the second cake layer on top and coat with more syrup and vegan whipped cream followed by chocolate curls and some fresh cherries if desired.
Serving and Storage
Refrigerate the cake in an airtight container for up to 2-3 days. It is nest served on the same day its made. Remove from the fridge for up to an hour before serving.
Nutritional information is based on the cake without vegan whipped cream.
Defrost the cherries over a sieve or colander on top of a bowl for a couple of hours and reserve the drained juice for the recipe. This saves you from buying extra cherry juice, and you can top up the juice with a little water if the amount doesn't quite add up.
Measure the recipe in grams: As with all baking, measuring with a kitchen scale will always give you the most accurate results.
Don't overmix the cake batter: this can cause the gluten to become overworked.