If you have an airbrush and have been afraid to use it here's an idea to get you started:) Choose 2 rainbow colors. In this case I used blue & pink. Spray about 1/2 the cake w/blue then the other 1/2 with the pink. In the center the colors will overlap and turn purple/lavender. Then mark off a center section w/a border and write the message. Add top& bottom borders, some curling ribbon & sprinkle on some jimmies to complete this super fast cake. I've done this idea on all shapes of cake, using many