- For the filling and the topping:
- 6 free-range egg yolks
- 170g caster sugar
- 125ml maple syrup
- 450g butter, softened
- 3tbsp coffee extract
- 150g dark chocolate
- 500g sweet chestnut purée
- chocolate curls and edible glitter, to serve - watch
- how to make chocolate curls
- For the sponge:
- 6 large free-range eggs, separated
- 125g caster sugar
- 50g cocoa powder
- You will need:
- A 31cmx21cm rectangular tin, greased and lined with baking parchment
First make the filling. With an electric whisk, beat the egg yolks in a large bowl until pale. Put the sugar and maple syrup into a saucepan and heat gently, stirring, until the sugar has dissolved. Have a jug ready. Now bring it to the boil and, once it is bubbling, pour into the jug to stop it cooking. Add a little syrup to the egg yolks and beat on high. Slowly add all the syrup and keep beating until cool. Then whisk in the butter, a little at a time, with the coffee extract. Melt the chocolate and let it cool, then whisk into the eggs with the chestnut purée. The filling will keep for up to 1 week in the fridge.
Heat the oven to 170C, gas 3. For the sponge, whisk the egg yolks and sugar until pale and thick. Sift in the cocoa. In another bowl, whisk the egg whites until stiff and fold into the egg yolk mixture. Pour into the tin and bake for 15-20 minutes, until risen. Put a sheet of baking parchment on top and invert on to a chopping board. Carefully peel of the paper that is on top and roll up the roulade tightly using the baking parchment that is on the bottom to help you manoeuvre it.
Unroll the sponge and fill with a third of the buttercream. Roll up tightly then use the rest to cover the sponge. Use a palette knife to create the log effect, then decorate with chocolate curls and edible glitter. This chocolate log is best left in the fridge for a day to firm up before slicing, though it will keep, lightly covered, for 3 days.