This reimagined version of James’s ‘Cola Ham & All The Trimmings’ illusion cake is no less impressive. The sponges are a cross between a sponge and a brownie, so don’t worry if you don’t see a huge rise during baking. There are four layers to this cake. If you don’t have four sponge tins, simply make the sponge batter in two batches, two sponges at a time.
Heat the oven to 180°C/160°C fan/Gas 4.
Make the sponges. Place the chocolate in a pan with the butter. Melt over a medium heat, stirring occasionally until smooth. Remove from the heat and set aside.
Put the flour, sugar, cinnamon, cocoa powder and bicarbonate of soda in the bowl of a stand mixer fitted with the beater attachment and mix on low speed for 10 seconds, until combined.
Pour the buttermilk into a jug. Add the eggs and cola concentrate to the buttermilk, then whisk together.
With the mixer on low speed, add the melted chocolate to the flour mixture and combine for a few seconds. Pour in the buttermilk mixture, then mix until smooth and just combined. Do not over mix.
Divide the mixture equally between the 4 lined tins and smooth out with a palette knife. Bake for 20–25 minutes, until a skewer inserted in the centres, comes out clean. Leave to cool in the tins for 5 minutes, then turn out onto wire racks to cool completely.
While the sponges are still warm (but not hot), drain the cherries, reserving the syrup. Prick the warm sponges with a cocktail stick and brush 1 tablespoon of the syrup over each warm sponge. Roughly chop the cherries and set them aside to drain on kitchen paper.
Make the buttercream. Place the butter, cream, cola concentrate, vanilla, salt and vinegar in the bowl of a stand mixer fitted with the beater attachment and mix on high speed until smooth.
Gradually add the sifted icing sugar and cocoa powder, mixing until silky smooth and scraping down the sides of the bowl when needed.
Make the ganache. Place the chopped chocolate in a heatproof bowl with the butter. Heat the cola concentrate and cream in a small pan until just below boiling point. Pour the hot cream mixture over the chopped chocolate and leave to stand for 1 minute, then stir until smooth.
To assemble, peel the baking paper off the sponges. Set 1 sponge on a serving plate and spread with a quarter of the buttercream, then scatter over a third of the chopped cherries leaving a clear 1cm border around the edge. Top with another sponge. Repeat with another one quarter of the buttercream and another third of the cherries, then cover with the third sponge. Repeat with another quarter of buttercream and the remaining cherries, then cover with the remaining sponge, top side down.
Spread the remaining buttercream around the sides of the sponges and smooth roughly with a palette knife. Holding the palette knife at a 90-degree angle to the cake (or use a cake scraper), scrape away excess buttercream to achieve a semi-naked finish.
Pour the ganache over the top of the cake and, using the back of a spoon, make a swirl pattern in the top. Decorate with your choice of fresh edible flowers and a few fresh cherries.