I used this recipe for the cake and this recipe for the frosting with blue food coloring. One batch of the frosting just barely covered the cake and the middle layer and did the clouds. I made the rainbow out of jolly ranchers. See picture below. I shaped foil into a thin rectangle with sides folded up to prevent spreadinng and sprayed with nonstick cooking spray. Lined up jolly ranchers lengthwise, 3 rows. Cooked in oven on cookie sheet at 350 for 5-10 minutes until candy was melted. Remove from oven and let cool a little but not get hard, just pliable. Cover a large food can with foil and spray with nonstick cooking spray. Wrap candy around the foiled can to form rainbow and press to smooth and shape. Let cool until hard. Store in an airtight container until just before using. I wrapped mine in bubble wrap to make sure it didn't crack if bumped. Used 2-8 inch cake pans.
