This hazelnut raspberry mousse cake is a rich and nutty dessert that is perfect for fall. The cake is made with a hazelnut sponge cake, layered with a creamy raspberry mousse, and topped with fresh raspberries. The raspberry mousse is made with fresh raspberries, whipped cream, and gelatin, giving it a light and airy texture. The cake is then chilled until set, making it a delicious and indulgent dessert that is perfect for special occasions.