One-time Upper Peninsula resident Brigitta writes in with this:
I first encountered pasties when I went to college in the late 70’s in the western end of the peninsula. Although the largest ethnic group in the area are Finlanders, the pasty arrived when miners from Cornwall emigrated there to work in the copper mines. Just as in Cornwall, the pasty was a perfect meal for miners, and the Italians, Hungarians, and Finlanders that came to the area also adopted it as their daily meal. The upper peninsula of Michigan also had large iron ore deposits, so there were a lot of iron mines, but in the western area it was primarily copper mining that took place. The mines eventually played out and became non-economic to operate, but one can still see many abandoned mine shafts dotting the landscape. However, the pasty is practically a national dish, and every “yooper” housewife regularly makes them.
Nobody in the UP ever argues about whether or not there is a glaze (there isn’t) or if the crimp should be on the top or the side (the side). The big controversy is whether to eat it plain, with gravy ladled on the top, or ketchup. A true UP pasty is made with chopped beef, diced potatoes, chopped onions, and if you wish, you can add a very little amount of diced carrots or some diced rutabagas. Some fancy-schmancy tourist stands offer other fillings, and although I’m not necessarily a purist, and I believe in innovation, I cannot wrap my taste buds around a pasty filled with chicken and broccoli or some such.