Dorie Greenspan's Top Secret Chocolate Mousse (Mousse auChocolat)

"No funny business here: This chocolate mousse is simply melted chocolate that's thickened with egg yolks and lightened with whipped egg whites. Like your favorite chocolate bar is frolicking among the clouds. If you're comfortable whipping egg whites and incorporating them gently, as to not deflate that hard-earned air, then the recipe will be a cinch. Perhaps that's because Dorie, when she implored her friend Martine for the ingredients and instructions, was handed a Nestlé chocolate bar: All of the information was on the back. This recipe is from Around My French Table (Houghton Mifflin Harcourt 2010)...."