Luscious lemon flavors abound in this lovely cake. The cake is lightly flavored with lemon with the addition of fresh lemon zest and lemon juice. After baking the layers are split in half and each layer is filled with sweet and tart lemon curd. The entire cake is then frosted with an utterly delicious Mascarpone Cheese frosting which is a perfect complement to the lemon curd filling. Be sure and make the lemon curd a few hours, or even a day in advance to allow plenty of time for chilling.