Melt the butter in a casserole.
Brake the chocolate in bites and pour in the melted butter, stir until the chocolate is melted.
Add the sugar and mix well.
Add the flour, salt, baking powder and vanilla sugar in the mixture and mix well.
Place the batter in the fridge for 15 minutes.
Preheat the oven at 175 degrees Celsius.
Take out the batter from the fridge.
Place a baking paper on a baking sheet.
Make small balls of the batter and place on the baking paper.
Place in the middle of the oven for approximately 10 minutes. The shorter time in the oven the stickier inside you will get.
Take out and let cool down.