In a saucepan over low heat, stir together the hot coffee, whole milk and sugar until the sugar dissolves and the mixture is nice and warm.
Add the cinnamon, nutmeg and rum and stir again until warm.
Pour into a mug and top with grated chocolate (and whipped cream, if you wish!)
If you want to make the drink even more chocolatey, add 1 tsp of chocolate sauce to the saucepan with the coffee, whole milk and sugar. (Calories don't count in the winter, right?!)