Mocha tiramisu torte

Method

1. Heat the oven to 180°C/160°C fan/gas 4. Pulse the flour and walnuts in a food processor until finely ground. Add the butter, sugar, beaten eggs and coffee, then whizz to combine. Spoon into the prepared tin and level the top. Bake for 20-25 minutes until a skewer pushed into the centre comes out clean. Cool in the tin for 10 minutes, then turn out onto a wire rack to cool completely.
2. Meanwhile, line 2 baking trays with non-stick baking paper and draw 4 x 10cm x 20cm rectangles. Melt the chocolate in a heatproof bowl set over a pan of simmering water (don’t let the bowl touch the water). Stir, then spoon onto the trays to fill each rectangle. Chill for 1 hour to set.
3. For the filling, in a bowl, beat the mascarpone with the marsala and sugar. In a separate bowl, beat the cream to soft peaks, then gently fold into the mascarpone mixture.
4.  Cut the cake in half, then slice each half horizontally through the middle to make 4 rectangles. Put one on a tray lined with non-stick baking paper. Top with a third of the filling, then with a chocolate rectangle (trim if necessary). Repeat the layers twice, then top with the final cake rectangle. Cover and chill. Set aside the final chocolate rectangle.
5. To make the chocolate coating, put the gelatine in a small bowl with 3 tbsp cold water and set aside. Put the sugar, cocoa and cream in a pan with 5 tbsp cold water. Stir to make a paste, then keep stirring over a low heat until the sugar dissolves. Increase the heat and bring to the boil, stirring. Reduce the heat and simmer, then stir until thickened slightly. Remove from the heat, add the gelatine leaves and soaking liquid, then stir until melted. Strain through a fine sieve into a bowl, pushing the mixture through with a spoon. Leave to cool slightly.
6. Before the coating starts to set, remove the cake from the fridge and neaten the edges with a sharp knife. Pour the chocolate coating evenly over the torte, smoothing the sides with a palette knife if needed. Chill for at least 30 minutes.
7. To serve, transfer the torte to a plate. Break the remaining chocolate rectangle into shards and scatter on top with gold leaf or lustre, if using.