How to Make It
Preheat oven to 350°F. Prepare cake batter according to package directions. Divide batter among 3 greased and floured 6-inch round cake pans. Bake until a wooden pick inserted into center comes out clean, about 25 minutes. Cool cake layers in pans on a wire rack 10 minutes. Invert cake layers onto rack; cool completely, about 45 minutes.
Prepare Vanilla Buttercream.
Using a serrated knife, trim domed tops of cake layers to make them even. Spread buttercream between layers and on top and sides of cake. Arrange a ring of edible flower petals around base of cake to form a cuff. Place large edible flower on top of cake.