Mix flour with nuts, vanilla and wheat starch. Make a well in the mixture. Add egg yolk and chocolate chips. Make a shortcrust pastry with butter. Chill dough for 2 hours.
Knead shortcrust dough until smooth. Roll and cut off pieces to form small balls.
Flatten balls slightly and place on a tray with baking paper. Bake at 170° C convection oven for about 10 minutes. When cool, dip one half in the dissolved cake glaze. Place on greaseproof paper.
