Preheat oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer). Line two baking trays with baking paper. Chop the chocolate and melt in a bain-marie.
Cream butter, sugar, 1 pinch of salt and vanilla sugar with the whisks of the mixer. Stir in the egg.
Add the chocolate. Mix flour and baking powder and stir in. Roughly chop the mint bars and mix into the dough.
Using a tablespoon, place approx. 12 piles of dough on each tray at a distance and press them slightly flat. Bake the cookies one after the other in a hot oven as described in the basic recipe and let them cool down.