Procedure

Preheat oven to 180°C
Prepare a 30x35cm jelly roll pan by greasing it, lining bottom and sides with wax paper, and greasing wax paper.
Mix the cocoa powder and flour together.
Mix flour and cocoa powder.
Using electric beaters, beat the eggs and sugar for 5 minutes or until light and fluffy and increased in volume.
Sift the flour over the eggs and pour the butter around the edge of the bowl.
fold in gently but thoroughly.
Put pan into oven immediately. Bake for 12 minutes, just until cake is golden on top and tester comes out clean. Do not overbake.
Remove from oven.
Turn the jelly roll onto a clean towel previously covered with a little bit of extra caster sugar.
Roll the jelly roll together with the towel and allow to cool.

The filling
Put chopped white chocolate with the cream to melt in a pan over previously boiled water. When the chocolate is soft stir until smooth.
Repeat with the dark chocolate and the cream.
Leave to cool until it has the consistancy of cream.
Beat the white chocolate cream with electrics beaters until soft peaks form. Do not beat too much.
Unroll the jelly roll, remove the towel and spread the fillings. leave 2 cm free fo fillings on the ends.
Roll up again, without towel but using it to help roll.
Cut off one end on the diagonal and place it alongside the log to form a 'Y'.
Refrigerate for 1 hour to firm filling.
Spread the dark chocolate all over the cake and run the tines of a fork to create a 'bark' effect.
Keep cake refrigerated until serving; it is much easier to slice when cold and firm.
Before serving, surround cake with some frsh leaves and dust with icing sugar.