For the dough, stir together the sugar and eggs until frothy. Add butter and stir. Add the vanilla sugar. Mix the flour and baking powder, pour into the mixture through a sieve and stir. Weigh in the cocoa powder and continue to stir.
Heat the milk or whipped cream in a saucepan and melt the chocolate (I always use 100 g whole milk and 100 g dark chocolate) in it. Add the melted chocolate to the batter and stir well. Place the dough on a small baking sheet or in a loaf pan (greased or lined with baking paper).
Bake in a hot oven at 180 ° C top / bottom heat (approx. 160 ° C hot air) on the middle rack for approx. 20 - 30 minutes, depending on the oven and shape. Take out the cake and let it cool down
For the glaze, prepare 200 g chocolate or couverture and 70 ml milk or whipped cream as above and pour over the cake. Smooth everything out nicely and let it cool down.
Shape biscuits as a fence for the construction site decoration. Chop the duplos and fill the fences. Filling small construction site vehicles with Smarties. Halve the children`s bars and stack them.
The construction site can be designed according to your own interests. I baked this cake with my little niece. That`s why he`s a little crooked, but individual.