Beat the eggs with 4 tablespoons of hot water, into a fluffy cream. Gradually, add the sugar while stirring. Mix the flour with the starch, vanilla and baking powder and gradually add it to the egg mixture. Finally, beat it with the cocoa that you've dissolved in 3-4 tsp of hot water.
Pour the mixture into a mold with a diameter of 8.5″ (22 cm), lightly greased and covered with baking paper. Bake at 356°F (180 °C) for 30-40 minutes. Once cool, cut the layer into 2 or 3 separate ones.
For the cream:
Dissolve 2 packages of pudding and the starch in some of the milk. Put the remaining milk to boil together with the coffee and sugar. Dissolve 1/2 tsp cocoa in it and the starch while stirring. Flavor with vanilla and stir until thickened.
While the cream is still warm, mix in the butter. Bind the layers together with cream in a suitable tray. Finish off the top with cream. Cover the cake with melted couverture chocolate or make decorations as desired and let the cake cool for 2-3 hours before serving.