chocolate cupcakes with peanut butter icing

My daughter and I made some desserts for a wedding reception tonight to add to a long list of homemade desserts that others have made.  I made chocolate mint fudge and sugar cookie bars.  My daughter made these smooth-as-silk chocolate cupcakes with peanut butter icing.  It's the icing that's special, and the recipe is all hers! 
Erin- if you're reading this, think of this as a buckeye cupcake. :)

chocolate cupcakes with peanut butter icing (my daughter)
46 of your favorite chocolate cupcakes, baked and cooled

icing:
3 sticks butter
2 cups smooth peanut butter
4 cups powdered sugar

Melt butter.  Add the peanut butter and blend until thoroughly combined and creamy.  Gradually add the powdered sugar. 
Load a decorator's bag full of icing and go to town!  Add some chocolate sprinkles if you wish.