There are six layers of cake inside: red, orange, yellow, green, blue, and purple. They are thinner layers, about a third the size of a regular cake layer. The cake is filled and frosted with almond buttercream.
I used marshmallow fondant to cover the cake and sponge painted it with food dye. Instead of using water as a base to thin the food dye I used vodka because the alcohol dries faster than water and keeps the fondant from becoming too sticky.
I used three different sized star cutters to cut out yellow fondant to embellish the cake. Wire supports were shaped by wrapping it around a marker. Any cylindrical object would work for this, I just happened to have a marker nearby.