Bake 2-layer cakes. Trim each cake to 1 1/2 in. to make combined 3 in. high cake. Ice cake smooth with light blue buttercream icing. Use tip 16 and green tube icing to pipe pull-out grass bottom border. Use tip 3 and dark blue buttercream icing to print message on cake. Attach icing decorations to cake sides with tip 3 dots of icing. Position frame topper and candles.