ask granny
If she added the margarine (butter) to the hot milk/sugar/cocoa or if she let the mixture cool and added it to the marg. or butter that she had creamed. The former would set up more like fudge, while the second would be more of a "butter cream" type and would stay creamy.
i'm trying to replicate a "frosting" my mother used to make and not having a very good time of it. i always thought it was pretty much standard, but in my search have discovered that it was not a butter cream, nor a cream cheese, nor do i believe it was the "7 minute" since it was not fluffy. it...