Preheat the oven to 170.
Break the chocolate into pieces and melt it with the butter (margarine is also possible!) In a bowl that you put in a saucepan with hot water.
Beat the sugar with a pinch of salt, the eggs and the vanilla sugar until creamy. Mix the flour and baking powder together. Then stir the mix into the 'egg mixture' until everything is moist.
Pour the melted chocolate into the batter in a fine stream and stir it in well.
Spread the batter evenly over the baking molds and place them on a baking sheet. Let the muffins bake in the oven for about 20 minutes.
Take them out of the oven after the 20 minutes. And now the most important thing: LET IT TASTE !!