Chocolate French Silk Frosting

Mike brought home this recipe from his stint in Home Economics.
I'm not sure if I tried it but it sounds yummy.

Ingredients

22/3 powdered sugar
2/3 cup butter softened
2 oz. melted (unsweetened) chocolate (cooled)
3/4 tsp. vanilla
2 Tbls. milk or cream


Instructions

Blend together sugar, butter, chocolate & vanilla on low speed.
Gradually add milk and beat until smooth & fluffy.