Hervé This' Chocolate Mousse

It took a brilliant, adventurous chemist to discover the simplest way to make chocolate mousse at home. Hervé This, the father of molecular gastronomy, discovered how to make a flawless, creamy chocolate mousse out of just chocolate and water. Yes, that's it! No need to ever go out for the store-bought stuff again. This all happens fast as the mixture cools, so chances are you'll go too far on your first try. Don't worry—you can simply just return it to the pan, melt it, and start over. As you're making this recipe, keep in mind that three things can go wrong. But don't you worry, here's how to fix them. If your chocolate doesn't contain enough fat, melt the mixture again, add some chocolate, and then whisk it again. If the mousse is not light enough, melt the mixture again, add some water, and whisk it once more. If you whisk it too much so that it becomes grainy, this means that the foam has turned into an emulsion. In that case, simply melt the mixture and whisk it again, adding nothing. Simple solutions to simple issues, making this recipe pretty foolproof. Once you have the rhythm down, you can flavor it as you wish with liqueurs or coffee or spices, sweeten it to your liking, or just keep it dark and intense. In all of these scenarios, a little whipped cream up top is never a bad idea. Adapted from Molecular Gastronomy: Exploring the Science of Flavor (Columbia University Press, 2008)