Grate 25 g chocolate and chill (see tip). Finely chop 75 g chocolate. Bring milk, double cream, starch, sugar and vanilla sugar to the boil in a saucepan, stirring occasionally, and simmer over a low heat for about 2 minutes.
Stir in chopped chocolate. Pour the pudding into four glasses (each containing approx. 150 ml), allow to cool and chill for at least 1 hour. Decorate pudding with chocolate shavings.
TIP Grating chocolate: Decorative flakes can be removed directly from the bar with the peeler. To do this, refrigerate the chocolate about 30 minutes beforehand.