Mix the flour with powdered sugar, vanilla sugar, salt, ground walnuts and cinnamon, pile on the work surface and press in the middle of a trough - then beat in an egg. Distribute the butter in little flakes around the hollow and quickly turn everything into a dough with your hands. Form a ball and keep wrapped in plastic wrap for at least 2 hours.
Preheat oven to 180 ° C. Roll out the dough thinly, cut out the hearts and bake on a baking sheet lined with baking paper in the oven for about 10 minutes. Allow cookies to cool: coat one half with samba, the other half on top and press down. Melt couverture in a water bath, sprinkle with hearts and place on each walnut half - then leave to dry well.