Preheat oven to 180°C (350°F).
Mix sugar and eggs. Add flour and yeast. Then add melted butter. Mix.
Split the mix 2/3 - 1/3. Pour approximately 250 gr. (1/3) in a mixing bol and add chocolate powder.
Seed vanilly pod. Add in the other part of the paste (2/3) together with 1 tablespoon of rum. Mix.
Fill the 24x24 cm mold with the vanilla paste. Bake for 13 minutes. Leave to cool on a cake rack.
Then fill the 24x12cm mold and bake for 13 minutes. Leave to cool on a cake rack.
While baking the cake, chop dark chocolate and melt in a water-bath together with the liquid cream.
Cut in two pieces the vanilla cake. Cover with half of melted chocolate. Place the chocolate cake on top and cover with the rest of melted chocolate. Finish by a vanilla cake.
Icing : Mix powdered sugar with 2 tablespoons of liquid cream. Pour on top of the cake, make it look nice. Sprinkle chocolate vermicelli.
Refrigerate few minutes and cut the side, so it looks nice and also because it had the tendency to dry.