Prosciutto Di Parma; definately after the pie is done. Prosciutto Cotto on the other hand is excellent baked on the pie.
I have to agree... I just bought some Prosciutto di Parma at Central Market last week.... it is so silky and almost buttery with a very mild flavor compared to the domestic prosciutto... it would be a crime to cook it. OTOH, the domestic is more salty and "stringy" and I like it better with the edges slightly charred, so I put it on under the cheese, before the bake.
~sd