Thanks to reader Reese, I came across this short video by Eran Amir. Take a look at it and see if you can see how it was done. After the jump, you can see a behind-the-scenes look at the filming of it.
It looks like one of those things that are shown in the reverse of the real action but it is not. Here is how they did it.
I am still not sure how they did the bit where the sandwich emerges from his mouth. It has to be some kind of sleight of hand where he has it up his sleeve or something but I don’t see it.