Hershey's "Perfectly Chocolate" Chocolate Frosting

Seriously the best Chocolate Frosting EVER. I could eat this without the cake if given the opportunity.

1 stick butter or margerine
2/3 c. Hershey's Cocoa
3 c. powdered sugar
1/3 c milk
1 tsp. vanilla

1. Melt butter
2. Stir in Cocoa
3. Alternately add sugar and milk, beating on medium speed to spreading consistency. Add more milk if needed. Add vanilla

Makes 2 cups