Mix flour, baking powder, sugar, vanilla sugar, salt, butter, egg and ground almonds in a bowl. Knead ingredients into a dough, shape into a ball and wrap in plastic wrap. Let dough rest for 30 minutes in the refrigerator.
Roll out dough on a floured work surface until about 3-4 mm (approximately 1/5 inch) thick roll and cut out star-shaped cookies with a cookie cutter. Cut out smaller stars from the middle each cookie. Place all cookies on a baking sheet lined with parchment paper and bake in preheated 180°C (approximately 350°F) oven for about 12 minutes until golden brown. Remove cookies from oven and allow to cool slightly.
Place cooked cookies side by side on parchment paper.
Chop chocolate and melt with palm oil over a hot water bath. Let chocolate cool slightly, place in a freezer bag, cut a small hole in the corner and use as a piping bag to decorate the cookies as desired with chocolate. Allow chocolate to dry and store in a container.