Cream butter with powdered sugar, vanilla sugar and eggs.
Mix flour with baking powder, nuts, cinnamon and cocoa and stir into the mixture.
Cover baking tray with baking paper and spread 2/3 of the dough thinly (approx. 5 mm) evenly on it. Stir through the currant jam and spread on the dough. Put the remaining dough into a piping bag and pipe a grid.
Bake at 175 °C for approx. 30-35 minutes.