Milk Chocolate Mousse Cake

For this type of chocolate mousse cake, baked cake layers are filled with chocolate mousse. (For another kind of cake that is basically a baked mousse, see the Cinnamon-Scented Baked Chocolate Mousse Cake.) This recipe is adapted from one by my friend Loretta Sartori, who runs a baking education program in Melbourne, Australia. I love the fact that the mousse sets only from the addition of the chocolate, without the use of gelatin, making it so much more d