I'm fairly happy with mine, it's simple and tastes good, but I'm hardly a chef so I'm sure it can be improved. Bonus points if its simple enough to do when you're tired as hell and just want a nice drink.
Start heating milk on low heat, then slowly add sugar and cocoa powder while mixing, 1 tbs each per 4oz of milk. I find this pushes the saturation limit of the milk a bit too close, so I add some more in to make sure everything dissolves. Add in some cinnamon, along with a pinch of nutmeg and salt. Once hot splash in a bit of cool cream and serve.