Preheat the oven to 350 degrees F and line a muffin tin with 12 paper cupcake liners.

In a large bowl, beat with a hand held mixer or a stand up mixer the cake mix, water, oil, eggs and pudding mix until the mixture is smooth and creamy.

Then divide the batter evenly into 6 small bowls.  Use the gel food coloring to dye each bowl of icing a different color of the rainbow.  I used red, orange, yellow, green, blue and purple.

Place each color of the batter in a ziplock bag and cut off a small piece of 1 of the corners. Gently pipe layers of the batter into the cupcake tins. I started with purple, then blue, then green, then yellow, then orange and finally red.  Make sure to layer the batter on top of each other as evenly as possible and do not swirl the colors together.

Bake for 15-18 minutes until a toothpick inserted into the middle of the cupcakes comes out clean.  Then allow the cupcakes to cool completely.

FOR THE ICING:

In a large bowl cream the butter until smooth.

Beat in the confectioners sugar (one cup at a time) on low speed until well combined.

Stir in vanilla and milk.  Whip until thoroughly mixed and fluffy on a medium-high setting.

Then icing the cooled cupcakes.  I used a star tip with a decorator’s bag to decorate the cupcakes.  Then top the cupcake icing with the rainbow sprinkles.

Serve and enjoy!