Method

Melt chocolate and butter together and set to one side
Add a splash of cream - mix til glossy
Separate your eggs
Whisk yolks and sugar together until fluffy and pale - add 2 tblpoons coco powder - plus 1 tbl spoon choc butter mix fold it in.
Whisk whites until firmifying/fluffy.
Fold whites and yolk mix together.
Put it on a lined baking tray - and bake it on 160 degs. for 20 mins. aprox.
Allow to cool - whip the remaining cream until soft peaks -
Lay it out on baking parch that's springled coco lay it face down - peel of the baked piece of paper spread choc, spread cream - roll it up

(Gather your excess coco powder back into your coco powder pot for next time.)