Black forest gâteau

Method

1. Heat the oven to 180°C/160°C fan/gas 4. With an electric mixer, beat the 175g butter with the caster sugar until pale and fluffy. Beat in the eggs, one at a time, then the vanilla, 100g melted chocolate, flour, cocoa powder and bicarb until combined. Finally, beat in the 150g soured cream. Divide between the
   2 prepared tins, level the tops and bake for 30 minutes or until risen and springy to the touch. Cool the cakes in the tins for 5-10 minutes, then turn out onto a wire rack to cool completely (see Make Ahead).
2. To make the chocolate shards, lay out the baking paper on a work top, then spread thickly with 300g melted chocolate. Roll up the paper straightaway, then put in the freezer to set.
3. Make the buttercream by beating the butter with the icing sugar in a large mixing bowl until light and fluffy (put a clean damp tea towel over the bowl when you start mixing to stop a cloud of icing sugar from escaping). Once the mixture is fluffy, beat in the soured cream and vanilla.
4. For the filling, put the double cream in a large mixing bowl, add the icing sugar and 1-2 tbsp of the kirsch, then whisk to soft peaks using an electric mixer.
5. Put one of the sponges on a cake stand or plate and drizzle with 2 tbsp of the kirsch from the cherry jar. Spread over the cream, then scatter with half
   the drained cherries. Sandwich the second sponge on top and use a palette knife to cover the top and sides of the cake with the buttercream icing.
6. Meanwhile, put the remaining kirsch in a small pan and simmer over a medium heat until the liquid is reduced and thick and syrupy. Set aside to cool.
7. To decorate the cake, take the rolled chocolate paper out of the freezer and leave at room temperature for 5 minutes. Carefully unfold and separate into long shards. Dust with cocoa, then stick the shards around the side of the cake. Arrange the reserved cherries on top, then drizzle with the reduced kirsch.