Polly wrote:

>It's the ordinary 'in every cookbook'
> recipe where you bake a sheet cake and
> pour a chocolate frosting on top while
> the cake is still hot out of the oven.
********>Butter, powdered sugar, milk, >cocoa, and bit
of salt and a little vanilla.

I'm not sure what size cake you are talking about, but this is the
chocolate frosting I've been making for more years than I can count, and
it is "cooked" and then put on the cake immediately (while still
pourable) on a hot cake and it firms up in a short time. This is for a
15 x 10 inch (jelly roll size) pan.

Frosting:

1/2 cup butter
4 tbsp. baking cocoa
6 tbsp. milk

Bring this to a boil and remove from heat and add a 1 pound box of
powdered sugar. Beat till smooth and pour over hot cake.
NOTE: It doesn't call for vanilla, but I usually add some anyway to
anything chocolate flavored. A person can use margarine, but I prefer
using butter for all my baking, and I also use evaporated milk for my
baking, unless it specifically calls for another kind, but in this case
I use half evaporated and half water, but for most frostings I use
undiluted evaporated milk, with great results. If the frosting you are
questioning is not cooked, then she could have just kept adding more
powdered sugar (I always use C&H) until the thickness she wishes. I've
never had a failed frosting.

Judy