For the muffins with chocolate drops, mix the butter, sugar, salt and vanilla sugar until the mixture becomes fluffy. Then add the eggs, continuing to mix.
Mix the flour and baking powder and stir in with the milk. Add half of the chocolate drops and mix well with the batter.
Pour the batter evenly into the muffin cups, sprinkle with the remaining chocolate drops and bake in a preheated oven at 200 degrees for about 15 minutes.