We gather and measure out all the ingredients, the fan oven is set to 160ºC, and we line a swiss roll tin with greaseproof paper ready to take the roulade mix. First of all, the chocolate is melted (in a glass bowl over some warm water). Whilst this happens, we whisk the egg yolks with 175g caster sugar until it is pale and creamy. Then the melted chocolate gets mixed in.
In a large, clean bowl the egg whites are whisked until they form stiff peaks. A tablespoon of this is then added to the chocolate mix to loosen it a little. Then the remainder of the egg whites are carefully folded into the chocolate mix.
The mix is poured into the lined swiss roll tin and gently levelled. It is then baked in the oven for about 20 minutes until spongy to the touch.
When it comes out of the oven, it looks like this. It is cooled in the tin for about 5 minutes during which time, a piece of baking paper is put on the work surface and sprinkled with some sugar. The roulade is then turned out of the tin onto the baking paper. The baking paper used in the tin is then carefully peeled from the roulade before covering with another sheet of baking paper which is then covered with a damp tea towel. It is then left to cool for an hour.
Leaving the roulade to cool, we move onto making the filling. For this, we melt the chocolate over a pan of boiling water. Half a can of chestnut puree, sugar and brandy are mixed together and the melted chocolate is added and stirred in. This is then spread over the roulade. Next a layer of creme fraiche is spread over.
Then it is time to roll the whole lot. We roll the long side and use the baking paper to help the process. *
Finally, the chocolate fudge icing is made by melting the margarine and milk in a pan which was allowed to cool slightly. The milk/margarine is then added to the sifted icing sugar and cocoa powder and mixed well. Then, the roulade is covered in the icing. Using a fork, the icing is decorated to resemble the texture of the bark, sprinkled with sifted icing sugar and chilled.
The roulade freezes well iced or un-iced. We cut ours one third/two thirds and freeze a third when it's made at Christmas for having over New Year.
It is delicious and never lasts long... it's supposed to serve 10 but that depends on how thick the slices are.
* The roulade can be frozen at this stage. Defrost thoroughly and ice before serving.