200gchocolate - preferably of good quality, chopped up
200gwater
Method
Place chopped-up chocolate in a big bowl, and prepare an ice bath (with a towel on the bottom to hold it in place).
Bring the water to a boil, then pour over the chocolate and stir until all the chocolate has melted.
Place the bowl of melted chocolate over the ice bath and whisk until the mixture thickens (~5 minutes).
The chocolate will thicken all of a sudden, so do watch for this and remove from the ice bath as soon as you see this happening, lest it’ll turn hard and clumpy if left to cool too much. Don’t worry if this happens though, just heat the bowl over a water bath/bain-marie, stir, and the mousse will come together again!
Keep and serve at room temperature (it goes hard when chilled). If not having immediately, keep it in the fridge, and heat it over a bain-marie and whisk a little before consuming to soften it.
Notes
If you don’t want a hefty forearm workout from all the whisking, use an immersion blender or an electric whisk.