Mix 45 g of powdered sugar with the vanilla powder, a pinch of salt and the milk until smooth. Then continue to stir the mixture in a boiling water bath until it becomes really thick. After that, cover it with a lid and chill it.
Whisk the beaten soft butter, the warm softened chocolate, the remaining 45 g of powdered sugar and the egg yolks to make a drift.
Spoon the cooled pudding mixture into the beaten mixture and whisk to a fluffy cream.
Drizzle rum over the sponge cakes, perhaps before piling them on top.
Now, on an oblong base (made of cardboard), layer three times three biscotti (that is, three groups of three in a row), then a pencil-thick layer of cream, then another three times three biscotti, again with cream on top.
Now come three times two biscotti, again crem and on top three times two biscotti glued together with crem placed vertically.
Next, use the remaining creme to spread the holes on the sides so that the cross-section is nicely triangular and no more biscuits stick out.
Sprinkle with chocolate sprinkles, set and cut into portions.
From the recipe collection of Andreas Kohout
Tip: Feel free to use better chocolate – the more delicious the result!