19 cake Rainbow fun ideas

This Rainbow Cupcake Recipe is so easy and starts with a cake mix. Top the rainbow cupcakes with a homemade marshmallow buttercream and some fun decorations! These are such a fun and easy way to celebrate! These are my favorite EASY Rainbow Cupcakes! Start with a box mix for the cupcake but make a homemade marshmallow buttercream frosting and FOUR different ideas for topping!