First, preheat the oven to 300 °F / 150 °C. Prepare a baking tin and line it with baking paper.
Crush the cookies in a small bowl, add sugar, cocoa and melted butter. Mix and line the tin with this mixture.
In another bowl, beat the cream cheese until smooth. Gradually add sugar and one egg at a time. Mix thoroughly after each one. Add the vanilla sugar that you mixed with the sour cream. Divide this smooth mass in half.
Spread one half over the crushed cookies and set the other aside.
Heat the melted dark chocolate in a water bath and mix it with the other half of the cream.
Put it in a plastic bag or pastry bag and create chocolate balls in the cream cheese layer.
Place in the oven and bake for about 1 hour. Then, turn off the oven, but do not remove the cake. Let it stay in the oven for another hour and then let it cool in the fridge for 24 hours.
