Hot Buttered Rum

For some reason, people have gotten into the habit of thinking that in order to make a Hot Buttered Rum, you need to use a batter mix. This means either taking the time to mix it up from scratch yourself, or buying a pre-mix from the store. Either way, you will end up with far too much if all you want is a single drink. There isn't any reason why you can't mix up a Hot Buttered Rum ala minute, so why not?

Hot Buttered Rum  

Garnish: Freshly grated nutmeg and optionally a stick of cinnamon.
Put the butter and sugar into a pre-heated mug and add the boiling water. Stir to dissolve, then add the rum and stir again.