Knead a firm shortcrust pastry from the ingredients and place in the refrigerator to rest.
For the nut topping, bring butter, sugar, vanilla sugar and water to a boil. Remove the pan from the heat and stir in the rum and nuts.
Roll out the short pastry, place on a greased baking sheet and spread with jam. Sprinkle the nut filling on top and bake at 150 °C for about 30 minutes.
Cut the nut wedges horizontally, vertically and crosswise while they are still lukewarm.
Melt the chocolate coating in a water bath. Coat the cooled nut wedges with the melted chocolate icing or garnish.