For the flash chocolate cake, break the chocolate into pieces and melt together with the butter over a hot water bath. Fold in the baking powder, almond kernels, sugar, vanilla sugar, salt and finally the eggs. If the dough is very liquid, fold in some more flour.
Pour the chocolate batter into a cake springform pan (diameter 26 cm) lined with baking paper and bake in a preheated oven at 160 °C (convection oven 140 °C gas mark 2) for about 40 minutes. After cooling, the dough should still be slightly sticky on the inside.
Cut 1.5 cm long strips of paper, place them on the Blitz chocolate cake and dust the whole thing with powdered sugar. Carefully remove the paper strips.