Knead 150 g flour, 50 g sugar, 1 vanillin sugar, 1 pinch of salt and 100 g butter in pieces first with a hand mixer and then briefly with your hands until smooth. Cover and chill for about 30 minutes.
Grease a springform pan (26 cm Ø) and dust with flour. Roll out the dough on some flour in the size of a mould bottom. Place in the mould, prick with a fork more often. Bake in the preheated oven (electric cooker: 200°C/circulating air: 175°C/gas: level 3) for about 12 minutes.
Finely chop the chocolate coating. Bring 150 g cream to the boil in a small pot, remove from the heat. Melt the couverture in it while stirring. Cool down for about 20 minutes.
Close a cake ring around the cake base. Pour in the crème and smooth it down. Chill for about 2 hours.
Whip 250 g cream and espresso powder until stiff, adding 1 vanillin sugar, 1 teaspoon sugar and cream setting agent. Fold in rum. Spread on the chocolate cream.
Whip 250 g cream until stiff, pouring in 1 teaspoon of sugar. Pour 4 tbsp. cream into a piping bag (small star-shaped spout), spread the rest on the espresso cream. Decorate the cake with cream tuffs. Chill for about 2 hours.
Decorate with cocoa and truffles just before serving.