After seeing the pie thread, I thought some people might be glad to hear there's a stall selling Cornish pasties at the Herbstmesse.
They're tucked away in the back corner of the Münsterplatz, right by where where you'd walk down the steps to the Rhein ferry.
I tested one - just for your benefit, you understand - and mighty fine it was too. They have pictures of Prince Charles on the window, but I'll forgive them that minor point