Preheat your oven to 180C/160C Fan, and line four 8"/20cm cake tins with parchment paper.
In a large bowl or stand mixer, beat together your Butter and Sugar until light and fluffy.
Add in your Flour, Cocoa Powder and Eggs and beat again till a delicious cake mixture is formed.
Split evenly between the four tins and the bake in the oven for 30-35 minutes, or until baked through. A skewer should come out clean!
Leave the cakes to cool in the tins for 10-15 minutes, and then cool full on a wire rack.
For the Buttercream
Make sure your Unsalted Butter is at room temperature, and beat on its own for a few minutes to really make it supple.
Add in the Icing Sugar a little at a time, and beat fully.
Add in the Vanilla and beat again till combined.
For the Ganache
Add your Chocolate and Cream to a heatproof bowl/jug, and heat in the microwave in 15-30 second bursts on low power stirring fully each time till melted and lovely.
Leave the Ganache to sit, stirring every now and again, till a peanut butter like consistency is formed. You can do this in the fridge or at room temperature, just make sure to not let it get rock solid.
For the Assembly
Drain the Cherries from the jar, keeping the liquid in a bowl.
Add a smidge of Buttercream onto the cake board or plate you are using to secure the cake. Add the first sponge on top.
Drizzle over some of the kirsch liquid from the bowl.
Spread over some of the Buttercream, and a little Cherry Jam, and some Cherries from the jar.
Repeat this process with the next two sponges!
Add your final sponge on top, and drizzle with the kirsch.
Using some of the buttercream, do a crumb coat on the cake - use an angled spatula or similar to spread the buttercream around the cake thinly, filling in any gaps there may be and so that the sides of the cake are flat.
Put the cake in the fridge for 15-20 minutes or so to set the crumb coat.
For the Decoration
Once your Ganache is at the peanut butter consistency, and your crumb coat has set, slather on the Ganache with an angled spatula, and smooth around the edges with a large metal scraper till smooth.
Add some to the top of the cake and smooth this over so that the cake is sealed in the ganache.
Set the cake in the fridge for 15-20 minutes again till the ganache is solid.
Let the chocolate sit for 5 minutes or so to set itself.
Pipe on top of the cake with the rest of the Vanilla Buttercream (and a 2D closed star piping tip), and add fresh cherries to the top of the cake and some sprinkles.
If you are decorating the cake board, spread/brush some leftover ganache onto the board.
Set the cake in the fridge for the final time and then enjoy!
All of the decoration is optional - I just described and put the recipe everything I did for the cake.
You can bake the cake into two tins instead of four if you don't have four - just use deep 8"/20cm cake tins, and bake for longer!
You can make a half size cake by literally halving the recipe and baking into two tins.
I would not recommend using fresh cream in this cake in place of the buttercream as it's not sturdy enough to then stack and ganache.
If you can't access Opies black cherries in kirsch, make your own by soaking some cherries in a bowl of kirsch overnight before baking.
You can make the ganache the day before as well to make it quicker the following day, but you will need to very carefully re-heat the ganache to the consistency you want and you don't want it to split.
Alternatively you can make the ganache first, and leave it to do its thing whilst you do the rest and it should be ready in time!