Err, wait... pre-baked? As in brownies that are already done that you simply heat up? I saw a commercial for those recently. Like the kind you microwave?

I don't think this would work. It's generally accepted that THC has to come into contact with both fat and heat to become activated. Meaning, each and every THC particle you expect to be consumed must come into contact with a fat particle. This isn't possible if the brownies are already baked.