Cream Cheese Frosting:In the bowl of your electric mixer, or with a hand mixer, beat the cream cheese and mascarpone cheese until smooth. Add the vanilla and confectioners sugar and beat until smooth. Using the whisk attachment, gradually add the heavy cream and whip until the frosting is thick enough to spread. Add more sugar or cream as needed to get the right consistency.
Assemble: With a serrated knife, cut each cake layer in half, horizontally. You will now have four cake layers. Place one of the cake layers, top of the cake facing down, onto your serving platter. Spread the cake layer with a layer of frosting. Place another layer of cake on top of the frosting and continue to frost and stack the cake layers. Frost the top and sides of the cake. Can garnish the cake with sweetened or unsweetened coconut.