How to make
Start with the ganache. In a metal bowl mix the broken chocolate into small pieces and the cream. Place over low heat and stir until the chocolate has completely melted and remove from the heat.
Stir the chocolate mixture periodically to prevent it from forming a crust until it cools completely. Beat the cooled and already thickened chocolate ganache with a mixer on the high setting of the mixer.
For the chocolate cake layers, beat the eggs with the sugar and vanilla sugar until the sugar dissolves. Add the oil, yogurt and mix again.
Separately sift the flour, cocoa and add the baking powders. Mix. In a blender, grind the cookies into coarser crumbs.
Add the mixture of flour, cocoa and baking powder first into the egg mixture and then the cookie crumbs. Mix until a homogeneous mixture is obtained.
From the mixture, bake 4 cake layers in a cake tin (diameter 24 cm) lined with baking paper at 360°F (180°C) for about 20-25 minutes.
Leave the cake layers to cool and in the meantime boil the syrup and let it cool.
Pour the cooled syrup evenly over the cake layers and begin to assemble the chocolate cake, alternating cake layers and ganache and finishing off with ganache.
To decorate the Oreo Cake I used melted chocolate with hazelnuts and sponge cake crumbs!