Heat the cream. Be careful, because it must not boil. Then remove from heat, add the chocolate broken into pieces and melt while stirring. Let the mixture rest overnight in the refrigerator.
Beat the egg yolks with 50 g of sugar until foamy. Stir in the cocoa, oil, milk, flour and baking powder. Beat the egg whites with 20 g sugar until stiff and fold into the batter.
Pour the batter onto a 21 x 21 cm baking sheet lined with baking paper and bake in a preheated oven at 180 °C for about 15 minutes.
Beat the chocolate cream with a hand mixer to a thick cream and spread it on the cold cake. Dust with cocoa powder and serve