Pour it into an greased and floured tray. Bake in a preheated 356°F (180 °C) oven about 25 min.
Once the cake layer is ready, it's time to make the cream. Pour 1/2 the milk in a pot, stir the other 1/2 with the flour to obtain a homogeneous mixture.
Shortly before the milk on the stove comes to a boil, pour the other mixture into it in a thin trickle. Stir nonstop, otherwise the cream may end up lumpy.
Once the cream obtains the desired consistency, remove the pot from the stove. Add the crumbled dark chocolate and stir. Within just a few min., the cream will obtain a chocolate flavor and color.
Cut the layer into 3 parts with a string and pour chocolate mixture over each.