Line the base of the tin with baking paper, grease the rim. Beat the eggs in a bowl with a whisk attachment, add the butter, sugar, and vanilla sugar and beat again until light and fluffy and the sugar has dissolved completely. Add the nuts, chocolate powder and milk and mix well. Mix the flour, baking powder and salt, sieve into the mixture, fold in and transfer to the prepared tin.
Approx. 1 hr. on the bottom shelf of an oven preheated to 180°C. Remove from the oven, allow to cool slightly, remove the tin frame, slide the cake onto a cooling rack and leave to cool completely. Dust with icing sugar.