Put instant coffee powder and sugar in a coffee mug.
Add 1 tsp. water and mix.
Beat the mix vigorously with a spoon. You have to incorpotate as much air as you can. That will give you the whipped frothy coffee-sugar mix. The more you beat, the mix will become pale in colour. Make sure your mix is whipped and creamy enough.
Heat a cup of milk and pour it over the whipped coffe-sugar paste. Stir. Sprinkle cocoa powder and serve immediately.