Either mix all ingredients in a mixer or shake them in a shaker. Beware that the latter procedure results in a lot of pressure built up, as the hot fluid heats up the air in the shaker, so you need to be careful and release some pressure during shaking, lest the lid of the shaker might blow off, painting your walls in a nice coffee-cocoa brown. If you feel fancy, feel free to add some hazelnut flavoring.
There you have it. A tasty drink to start your day, with everything that's unequivocally good for you: Protein and caffeine.