Make this chocolate roulade with good quality chocolate to produce the finest flavor.
Preheat oven to 375 degrees F.
Grease and line with parchment paper a 12" x 16 1/2" baking tray
Put the egg yolks and 3/4 cup of the confectioners sugar in a bowl and beat until very light and mousse like. The beaters should leave a ribbon-like trail when lifted out of the bow.
Sift the cocoa into the bowl and gently fold in with a large metal spoon.
Put the egg whites in a bowl and beat until soft peakes form.
Beat in the remaining confectioners sugar, 1 tablespoon at a time, until stiff peaks form.
Fold into the yolk mixture in 3 batches.
Gently spread and even layer of mixture on the prepared tray.
Bake for 8-10 minutes, until firm to the touch.
While the cake is baking, cover a large wire cooling rack with a damp cloth that is topped with a sheet of parchment paper.
Tip the cooked sponge onto the rack, then lift off the baking tray, peel the parchment off the bottom and let cool.
To make the dark mousse:
Put the chocolate and butter in a heatproof bowl set over a saucepan of steaming, not boiling
water and melt gently.
Remove from the heat and gently stir in the yolks, then the rum, if using. Let cool.
Put the eggwhites in a bowl, beat until stiff, then add the sugar and beat again until stiff.
Fold into the chocolate mixture in three batches. Chill priefly until starting to set.
To make the white mousse:
Chill the whipped cream if necessary, then fold in the grated chocolate and chill util ready to assemble.
Sprinkle the sponge cake with rum if using.
Spread the dark mousse on top, leaving a 3/4 inch border of sponge all around.
Cover with white mousse, then roll up from the narrow end like a jelly roll, using the parchment paper to help you.
Wrap in the parchment paper to give it a neat shape then chill for about 30 minutes up to 2 hours.
When ready to serve, remove the paper and transfer the roll to a serving place.
Decorate by putting a thin layer of whipping cream so the garnish will stick
a) cover with the chocolate freckles, put some whip cream into a piper and pipe a rosebud on each serving with a marishino cherry on the top OR b) cover with finely grated chocolate OR c) sprinkle on confectioners sugar and cocoa.