For the fluffy cake, prepare a sponge dough from the ingredients and then bake it right away.
Then prepare a dough from the ingredients for the Sacher cake and bake it as well.
In the meantime, prepare a cream from the ingredients.
When both pastry bases are ready and cooled, spread the cream on the sponge dough and place the Sacher cake base on top.
The finished fluffy cake can now be served.