Prepare all ingredients.
Beat 1 egg + 3 egg yolks along with 90 g of sugar for 5 minutes.
Add the flour, starch, and cocoa.
Mix well.
Beat the egg whites very firm...
...and beat in the rest of sugar....
...Add them to the dough.
Pour the dough on a baking sheet covered with buttered parchment paper.
Smooth using a rubber spatula...
...and bake 20 minutes at 180°C.
When finished, remove from the oven and leave to cool.
Beat the very cold liquid cream into whipped cream.
Add the liquor.
Place the biscuit on a cloth.
Remove the parchment paper.
Cover the surface of the biscuit with whipped cream.
Roll the dough with the help of the cloth.
Decorate the surface of the log with icing sugar...
...and chocolate shavings. Serve very cold.