For the nut wedges, knead flour, butter, sugar, egg, vanilla sugar and baking powder until a smooth dough is formed. Line a baking tray with baking paper. Roll out dough evenly on it and spread with apricot jam.
Preheat oven to 180°C. For the topping, melt butter, sugar and vanilla sugar in a large saucepan, stirring constantly. Mix the nuts with the water and stir in.
Spread mixture on top of the jam-covered dough. Bake for 20-30 minutes until the surface is golden brown. Cut the mixture into triangles on the baking sheet, let cool.
Melt couverture in a water bath and dip the edges of the cooled triangles. Serve the nut cookies.