Put 2-3 t butter and 1 T brown sugar in a mug. Fill the mug halfway with boiling water and stir to melt the butter and dissolve the sugar. Then choose your variation from below:

Traditional hot buttered rum
Add one shot of rum and either:
- A pinch of cloves and cinnamon
- A lemon twist

Mango hot buttered rum (thanks to Ivar’s for this idea)
Add one shot of mango-flavored rum and a splash of Southern Comfort

Coconut hot buttered rum
Add one shot of coconut-flavored rum and a splash of Southern Comfort

Maple hot buttered rum
Add one half shot of rum, one half shot of maple liqueur, and a twist of lemon