Puree the ice cream, 6 milk slices and the milk in short bursts. Danger! If you puree too long, you don`t get a shake, but mud. Ideally, even coarser pieces of milk slice can be seen (the size of a pea or rice grain).
Divide between four glasses, sprinkle with chocolate shavings and break the 2 last slices in the middle. Put on the shake, put in a straw, serve ice-cold!