Cut the butter in a dough bowl (food processor) and stir in the sugar, vanilla sugar, chestnut cream and egg until lightly foamy. Mix the baking powder into the flour, gradually add it to the dough bowl and work it into a smooth dough.
Cover the baking sheet with parchment paper and place the dough shaped with a teaspoon (walnut size) on top. Bake on the middle rack for about 12-14 minutes.