Put 4 chocolate bars aside for decoration. Warm 1 cup of cream while stirring. Add the remaining mint bars and let them melt. Cover and put in a cool place overnight.
Finely chop the nuts. Beat the fat, 1 packet of vanillin sugar and sugar in a mixing bowl with the whisks of the hand mixer until foamy. Stir in the eggs one after the other. Mix flour, cornstarch and cocoa (leave some for dusting) and stir in.
Stir in milk, fold in nuts. Pour the dough into a greased box form (20 cm long) sprinkled with breadcrumbs and bake in a preheated oven (electric range: 175°C/ gas: level 2) for 50-55 minutes.
Take the cake out of the oven and let it rest for about 5 minutes. Turn onto a cake rack and let it cool down. Cut the cake 2 times lengthwise. Whip the chocolate mint cream with the whisk of the hand mixer.
Spread half of it on the bottom cake layer, place the second cake layer on top and spread with the remaining cream. Cover with the rest of the cake base. Whip the rest of the cream until stiff, allowing the remaining vanilla sugar to trickle in.
Fill 3 tablespoons of cream into a piping bag with a star-shaped spout and set aside. Wrap the cake with the remaining cream, decorate with cream tuffs and dust with cocoa. Cut the chocolate bars in half. Decorate with chocolate bars and mint.
Results in about 12 pieces.