How to make
Beat the egg whites and yolks separately and add 1 cup sugar in gradually. Add the milk and the egg whites into the egg yolks, then the melted butter.
Mix the baking powder and salt with the flour and begin adding it to the mixture, while stirring constantly.
Set aside 1/3 of this mixture and add the pre-melted chocolate to it. To the other mixture, add the vanilla. Pour the chocolate mixture into a buttered and floured form first, then the light mixture, so that the dark dough remains on the side and bottom of the form.
Bake in a preheated oven, about 360°F (180 °C), for approximately 50 - 60 minutes, then leave to cool at room temperature (about an hour) and invert it out into a serving plate.
Optionally, sprinkle with powdered sugar or make a chocolate glaze.
