Cheaper and less sugary than Swiss Miss, and especially convenient where Swiss Miss is not available. Because it does not contain an emulsifier (? - is that the word?), the cocoa powder will tend to sink to the bottom of the drink over time.
3 teaspoons plain powdered milk
2 teaspoons sugar
1 teaspoon cocoa powder
Combine dry ingredients in a mug. Add boiling water and stir until dissolved. If desired, add a shot of real milk. Yield 1 mug cocoa.
You can also combine the dry ingredients in the same proportions, but larger amounts, to make 3-2-1 Cocoa mix.