Half fruity and half floral, cherry-blossom extract gives thiscake by Wendy Kromer a delicate flavor. Add just one drop of floral extract to 1 cup of buttercream.
Divide each 8-inch cake layer in half horizontally. Set aside 4 of the cut layers for the Cherry Blossom Cake; 4 for the Violet Cassis Cake; and 4 for the Rose Petal Cake.
Set one of the cake layers onto an 8-inch cardboard round, spread about 2/3 to 3/4 cup of the cherry blossom-flavored buttercream on top, then top with the next cake layer. Place about 3/4 cup of the cherry blossom buttercream into a piping bag fitted with a 1/2-inch-diameter pastry tip, and pipe a ring of icing around the edge of the cake layer (this will act as a dam for the pastry cream); spread the vanilla pastry cream inside the piped buttercream ring. Top with the next layer and spread 2/3 to 3/4 cup of the cherry blossom buttercream on top. Add the last layer, then spread the entire tier with the remaining cherry blossom buttercream. Chill the tier, then spread a final, smooth coat of buttercream and chill again. Make sure there are no bumps in the buttercream coating as they will be visible once the tier is covered with the rolled fondant. Lightly sprinkle cornstarch onto a clean, non-porous surface, then roll the pale pink fondant into a disk large enough to cover the top and sides of the tier. Fondant should be approximately 1/8-inch thick. Lift fondant using a rolling pin or your hands, then center it over the top of the tier and lay it over the top and sides, smoothing it with your hands. Trim excess fondant away using a pizza wheel.