Christmas yule log

Method

1.  Preheat the oven to 180°C/fan160°C/gas 4. Grease and line a 28 x 38cm Swiss roll tin with baking paper. Put 175g of the chocolate into a bowl over a pan of simmering water and heat gently until melted. Remove from the heat and stir until smooth.
2.  Put the egg yolks and sugar into a large bowl. Using an electric hand whisk, whisk until mousse-like, then whisk in the melted chocolate.
3.  In a dry, grease-free bowl, whisk the egg whites to soft peaks. Stir a little into the chocolate mixture, then carefully fold in the rest with a metal spoon. Pour into the tin and bake for 20-25 minutes, until spongy to the touch. Cool for 10 minutes, then cover with a damp tea towel. When cool, chill for at least 2 hours or overnight.
4.  While the roulade is chilling, make the filling. Mix the Nutella and mascarpone together until smooth. Gradually mix in the brandy. Cover and chill until needed.
5.  Carefully turn out the roulade on a sheet of baking paper. (At this stage, you can wrap it in cling film and freeze for up to one month. When ready to use, thaw at room temperature, then fill and roll.)
6.  Make the chocolate ‘bark’. Melt the remaining chocolate as before, then allow to cool for 10 minutes. Pour onto a baking tray lined with baking paper and thinly spread out with a spatula. Chill for 8-10 minutes, until the chocolate is firm but still pliable. Tear the chocolate into small jagged pieces. Put in a single layer on a large lined baking sheet. Chill for 15 minutes until crisp.
7.  Spread half the filling over the roulade. Holding the baking paper, lift up the nearest short edge to you and carefully roll up the roulade – don’t worry if it cracks. Transfer to a plate. Spread the rest of the filling over the top of the roulade, then arrange the chocolate on top, overlapping. Chill for 1 hour. Dust with icing sugar to serve.