Roughly break the chocolate and place in a saucepan with cocoa powder, vanilla sugar, cinnamon and sugar. Heat over low heat until the chocolate is dissolved.
Add milk and heat while stirring, but it shouldn`t boil! Take the saucepan off the stove and set it aside.
Mix the egg yolks with the sugar until frothy. Beat into the milk mixture together with the brandy.
Immediately pour into cups and serve with long cinnamon sticks to stir.