1

For the ganache, finely chop the dark chocolate and transfer to a large bowl. Put the cream and sugar in a saucepan and gently heat until almost simmering and the sugar has dissolved – don’t let it boil! Remove from the heat and cool for a couple of minutes, then pour the mixture over the chocolate. Let it stand for 3-4 mins before mixing gently from the centre with a spatula. Gradually move the spatula outwards to incorporate the chocolate. Pour the ganache into two deep baking trays, cover with cling film and refrigerate overnight.

2

Heat the oven to 180°C. Lightly butter and line 3 x 20cm loose-bottomed cake tins. Tip the flour, bicarbonate of soda, both sugars, a pinch of salt and the cocoa powder into a large mixing bowl. If there are any hard lumps of sugar, break them up using your fingers.

3

Whisk the eggs, vanilla extract and soured cream together in another large bowl. Set aside. Finely chop the chocolate and dice the butter, then add both to a saucepan and melt over a medium heat, stirring continuously, until totally combined. Set aside. Put the coffee granules into a jug and top up with the boiling water.

4

Pour the soured cream mix into the dry ingredients along with the coffee and melted chocolate. Fold together using a large metal spoon until combined – do not over-mix. Divide half of the mixture between the lined cake tins and pop into the oven for 15 mins. You can check if they’re cooked by poking each cake through the centre with a skewer – if it comes out clean, the cake is ready! If not, return the cakes to the oven for a couple of minutes.

5

Set the cooked cakes aside to cool, then turn them out onto a cooling rack. Clean the cake tins and repeat the process with the remaining cake mixture. Once the last three cakes are out of the oven and cool, you can remove the baking paper.

6

When you are ready to assemble, coat a sponge layer with a 1cm-thick layer of ganache, smoothing out with a spatula, then top with another sponge. Repeat, coating each additional sponge with the same 1cm-thick layer of ganache, until all of the sponges are stacked. Spread the outside of the cake with a thin layer of ganache and let it air-dry for a couple of hours, or preferably overnight – this will help set the cake so you don’t get crumbs in the icing. Cover with the remaining ganache then use a hot offset spatula or blowtorch to smooth everything out and make it shiny.

7

For the topping, finely chop the chocolate and set aside. Heat the double cream with the sugar in a small saucepan – don’t let it boil! Stir until the sugar is dissolved, then pour over the chocolate. Let it stand for 3-4 mins, then stir from the middle to slowly incorporate the chocolate. Let it cool and thicken, then pour over the top of the cake, spreading out with a spatula, encouraging it to drip down the sides. Let it set.

8

Heat a knife before cutting to make the ganache extra shiny inside.