2) Pull the pan from the heat and carefully pour the 60ml water into the caramel. Take care; it may spatter a lot. Whisk until smooth and allow to cool. (The burnt caramel can be held for up to 2 weeks at room temperature.)
3) When ready to serve, put 3 tbsp of the burnt caramel into 4 mugs or cups and top evenly with the chopped chocolate. Bring the milk to a simmer in a medium pan over medium heat. Pull pan from the heat and add the Goldschlager and rum; pour carefully over the chocolate. Serve with a spoon to stir the layers together.
Cook's note: Goldschlager is a cinnamon flavored liqueur with small flecks of edible gold.