Preheat the oven to 180 ° C circulating air (200 ° C top / bottom heat).
Slowly melt the butter on the stove. Crumble the biscuits very finely. This works best with a chopper, but also without problems in a freezer bag with a rolling pin. Then mix the crumbs well with the melted butter and press the dough flat on the bottom of a springform pan lined with baking paper. Pre-bake the base in the oven for 5 minutes.
In the meantime, separate the eggs and beat the egg whites until stiff. Mix the egg yolks in a second bowl with the quark, crème fraîche, sugar, vanilla sugar and vanilla pudding powder. Then fold in the egg whites. Put the mixture on the floor and distribute the children`s bars in small pieces on top.
Bake the cake for 25-30 minutes. Then switch off the oven and let the cake stand in there for a few more minutes. See if it already looks good, take it out and let it cool down.