- M&M's or Skittles
All it takes to chase the rainbow is a buttercream-frosted confection with four layers, and eight shades of milk chocolate lentils (candywarehouse.com).
Refrigerate the cake to firm up the icing, then add candy. Complete the bottom row, then work vertically in columns to cover the tier's lower half. Fill in the upper portion with a lighter hue, and move up. For a real dose of decadence, opt for chocolate cake and filling