A fluffy vanilla cake batter, dyed in rainbow colors, and made into a rainbow checkerboard cake!
* If you want to make a typical checkerboard cake, make only one of this recipe (both cake and icing), divide in two bowls for two colors (or add cocoa for a chocolate and vanilla version) and alternate so that one color is in the inner/outer rings of one pan and middle ring of the other. Because I made a 6-tier rainbow checkerboard cake, I made the recipe twice so I could use all the colors of the rainbow (with exception of Indigo).
** For baking purposes, it is best to have eggs, milk, and butter at room temperature.
*** You can substitute the seeds from a vanilla bean if you prefer, you will see dark flecks of the vanilla bean in the white icing.