Thanks everyone for the suggestions. Ghee and coconut oil seem like the best substitutes for margarine. Eggs are ok, but not dairy. I was all ready to make my own powdered sugar (which, BTW, is the same as confectioners sugar) without the cornstarch, but in the end, I chose the path of least resistance. I saved my frosting that I originally made with the "Enjoy Life" chocolate chips. It tasted better after being in the refrigerator, and spread better too. This is not to say that it was a great frosting. I just couldn't wait long enough to grind all my own sugar to make powdered sugar, to then make frosting just to eat that yummy Pamela's chocolate cake

For those of you who can't eat powdered sugar because of the cornstarch in it, here's how you do it (caveat - I haven't tried it yet myself):

Grind sugar in a coffee grinder, food processor, spice grinder, or blender for about 2 minutes. I've read various things about spliting it up in batches, which makes sense. Add about 1 tbsp potato starch, tapioca powder or arrowroot to 1 cup sugar. This is mostly to keep it from clumping, so if you are going to use the powdered sugar right away, you probably don't need it.

Ok, I just shoveled down two pieces of the cake. The frosting I ate is definitely better chilled, but doesn't taste as good at room temperature. Instant gratification has been satisfied, but I'll make sure to make the frosting first the next time !

Claire