For the dough, put the flour, cocoa powder, sugar, eggs, milk, baking powder, vanilla sugar and oil in a bowl and mix with a hand mixer. Mix in the chocolate chips and pour the batter into approx. 20 muffin tins.
For the filling, mix together the cream cheese, egg and sugar and spread the mixture over the dough with a teaspoon.
Bake the muffins in the preheated oven at 160 degrees circulating air for about 20-25 minutes on the middle rack.