Line an 8X8 baking dish with foil or parchment paper and spray with a non-stick cooking spray for easy removal of the fudge.
Melt the chocolate chips in a microwave safe bowl. Heat in 30 second increments and stir between each one. Heat until the chocolate is melted and do not overcook the white chocolate.
Stir in the vanilla frosting.
Then separate the mixture evenly into 3 bowls.
Stir in the pink, purple and blue food coloring into each one of the bowls until each bowl is your desired color.
Then drop spoonfuls of each color into the 8X8 pan using a random pattern.
Take a knife and run it through the fudge to create a swirl pattern.
Quickly top the fudge with the marshmallow and rainbow sprinkles and gently press them down into the fudge.
Refrigerate the fudge for 2-3 hours until the fudge is set.
Then remove the fudge from the pan using the parchment paper. Cut into squares and enjoy!
Notes
Store the leftovers in an airtight container at room temperature for up to 1 month or freeze for up to 3-4 months.