Place two and a half teaspoons of cocoa powder into a large mug.
Set a kettle of water onto boil.
Whisk up about 3/4 of the amount of milk you want in a small bowl until it becomes mildly thick and very frothy.
Pour the milk into the mug and mix with the cocoa powder until you have a brown, frothy milk mix.
Pour in water from the boiled kettle.
Add as much more milk as you want to.
Stir in two teaspoons of plain sugar.
Enjoy your sweet, very frothy cocoa!