Method

1. Preheat the oven to 180C/gas 4. Line a 30 x 20cm Swiss roll tin with greased baking paper.

2. Melt the chocolate in a bowl placed over a saucepan of simmering water. Leave to cool.

3. Whisk the egg yolks with the sugar until thick and pale.

4. Fold in the melted chocolate.

5. In a separate bowl, whisk the egg whites until they resemble soft peaks.

6. Fold the egg whites carefully but thoroughly into the chocolate mixture.

7. Spread the mixture into the prepared tin and bake for about 15 minutes, until just cooked and springy. Make sure you don't over-cook it otherwise the sponge will break when you it is rolled-up. Leave to cool.

8. For the filling, mix the chestnut purée and cream together.

9. To assemble, lay a piece of greaseproof paper over the work surface and dust with icing sugar.

10. Turn the roulade out onto the paper and gently remove all the lining paper from the roulade.

11. Spread the chestnut cream over the roulade.

12. Using the dusted paper to help, roll the sponge away from you. Trim the ends for a neat finish, but don't worry if the roulade cracks a little.

13. Dust the roulade with icing sugar and chill until ready to serve.