Mix the butter at room temperature with powdered sugar and vanilla sugar until it becomes a frothy cream.
Add eggs, whipped cream and continue mixing until it becomes a homogeneous cream.
Add the flavors and incorporate the flour mixed with baking powder.
I divided the dough into two equal parts: in one of the halves I incorporated the cocoa by kneading.
From the dough obtained we obtained two rolls as follows: I spread a white sheet in the shape of a rectangle and a black sheet and I put it over. I rolled it and covered it with cling film and left it in the fridge for 40 minutes. (I got a bigger roll and a smaller one ... plus the leftover dough from which I made various shapes that were obviously eaten :)))
Cut the slices according to the desired thickness and bake them in a tray lined with baking paper for 15-20 minutes.
It is kept in hermetically sealed metal boxes.