Pour the cold milk into a tall mixing bowl and - according to the instructions on the packet - beat with a mixer for 3 minutes to the vanilla cream.
In another container, whip the cream until stiff. Now pour the cream along with the rum and the grated chocolate onto the vanilla cream. Mix briefly with the whisk on a low heat and you`re done!
Split into dessert glasses and place in the refrigerator for at least 1 hour.