A mousse is a mixture of whipped cream and pudding. And, sometimes other flavors are added to create unique tastes. Mousse cakes were popularized in the late 19th century with chefs learning how to whip egg whites and chocolate in order to build layers of soft, fluffy cake that wouldn’t crack when stacked high with icing or coated in chocolate. The best part about mousse cakes is that they look beautiful and taste even better!