I’ve done a few cakes that had an iridescent effect on the fondant.
It’s a pretty look, and it makes the cake seem to be different colors when you look at it from different angles.
This feather cake was one of my all-time favorites.
To get the iridescent look, start with black or dark fondant feathers, and brush them with shiny multicolor luster dust.
If you’re putting the fondant directly onto the cake, make sure that you use an edible variety like Crystal Colors.
By brushing with the different colors, you’ll create a layered multicolor look that will seem to change color depending on how the light is hitting it.