For 12 Chocolate Muffins you need:

100g chocolate
50g chocolate powder
125g butter (room temperature)
2 egg
100g sugar
175g flour
150cc milk
1 teaspoon of baking powder
1 package of vanilla sugar

30g black and 100g white chocolate cut in little pieces

oven baking temperature: 180 C°
baking time: ~30min

Instruction:
1. Melt 100g chocolate at low temperature
2. Beat butter, sugar and vanilla sugar together until it becomes creamy
3. Add the egg + milk and continue mixing
4. Mix the flour with the chocolate + baking  powder and add it to the wet butter-sugar-mixture.
5. Add the melted chocolate and mix everything very well
6. Cut the black and white chocolate in little pieces and add it to the dough
7. Fill the dough into the baking cups and decorate them if you like
8. Bake the Muffins for about 30min and let them cool completely on a rack