Melt chocolate with butter in a double boiler. Beat eggs with sugar until foamy and add flour, cocoa and baking powder. Add chocolate and butter mixture and fold in. Preheat the oven to 160 ° C top / bottom heat and bake the cake in a greased springform pan for 30 minutes.
Heat the cream. Break the chocolate into pieces and place in a bowl, pour the hot cream on top and stir until the chocolate has melted. Spread the icing on the cake and let it cool down.