Using the paddle attachment on a stand mixer, cream the butter until light and fluffy.
In a measuring cup, combine the milk and the pudding mix until it's completely dissolved. If you do not dissolve it all at this point, you will have gritty icing!
Beat the pudding mixture into the butter completely.
Add in the powdered sugar, half a cup at a time, beating in completely.
Chill the icing for approximately 20 minutes, to allow the jello and the butter to set more completely.
Use to ice cakes and cupcakes.
Yield: Approximately 1 1/2 cups of icing. This will frost one standard sized bundt cake perfectly.