Brew some strong coffee, then half fill a 2 cup measuring cup with milk (skim milk gives the best foam). Microwave until almost boiling, about 1 minute and 20 seconds. Place a whisk in the milk. Holding the handle between your palms, vigorously rub your hands together so the whisk spins back and forth, creating foam. Partially fill a mug with the coffee, them pour in the hot milk, holding the foam back with a spoon. Ladle on the foam, then dust with cinnamon and cocoa powder.