Mix coffee and espresso powder and let it cool down. Separate eggs. Whisk butter, 100 g sugar, vanillin sugar and 1 pinch of salt with a whisk of the hand mixer for 5-10 minutes until white and creamy. Stir in the egg yolks one by one. Mix flour, 40 g cocoa and baking powder, sieve and stir in alternately with the coffee mixture. Fold in nuts.
Beat the egg whites and 1 pinch of salt until stiff, adding 100 g sugar. Fold the egg white into the dough. Grease a ring cake tin (approx. 2.5 litres capacity) and dust with flour. Add the dough. Bake in the preheated oven (electric range: 175 °C/ convection oven: 150 °C/ gas: level 2) on the second rack from the bottom for 50-60 minutes (test with sticks). Cover if necessary. Remove the cake and let it cool down for about 15 minutes. Remove the cake from the pan, turn it onto a cake rack and let it cool down completely. Chop the couverture, melt over a warm water bath. Mix 9 tbsp. water, 20 g cocoa powder, cream and 50 g sugar, bring to the boil, let cool down a little. Stir in chocolate coating.
Remove the cake and let it cool down for about 15 minutes. Remove the cake from the pan, turn it onto a cake rack and let it cool down completely. Chop the couverture, melt over a warm water bath. Mix 9 tbsp. water, 20 g cocoa powder, cream and 50 g sugar, bring to the boil, let cool down a little. Stir in chocolate coating. Cover the cake with it, sprinkle with espresso beans and let it set. Whipped cream tastes good with it
Waiting time 1 hour