You might as well ask: what sort of ingredients go into stew? Or pot pie? Or hash? Traditionally it was whatever was on-hand that day: pieces of meat and root veggies if times were good (beef, pork, mutton, chicken, rabbit), just the root veggies plus other miscellaneous “stuffings” when times weren’t so good.
What might those “stuffings” be? Well, one woman I met in Cornwall told me that in lean times, her mother would add broken-up chicken or rabbit bones to her father’s pasty filling. Why on Earth? Did she want to kill the man? Clearly no (at least I think). To hear this Cornish matron tell it, her mother simply didn’t want her father showing up for work with an anemic-looking pasty. It was a point of pride. Just like American construction workers used to peek at/in each others’ lunch pails to see how the Joneses were living, Cornish workers picked up clues to their coworkers’ prosperity by the relative rotundity of their pasties. Sending the man of the house off to work with a plump pasty was, therefore, a matter of honor. If there were some extra crunchy bits inside it, well, it was a small price to pay to keep up appearances. And anyway, provided you don’t choke to death on them, they’re good for you.
Mrs. Pastry would be the first to agree with that. In fact — did I ever tell you this story? — on our first date she ordered braised chicken and gobbled it down, bones and all. She’d just returned from the Dominican Republic, you see. She’d been serving in the Peace Corps there, and that’s how people ate. They couldn’t afford much meat (just like those Cornish workers) so when they had a little, by heaven they made the most of it. The wife came to enjoy that, and it definitely made an impression, friends. I knew right away that this was a very, very interesting girl.
But back to what I was talking about. Cornish pasties, being a make-do food, had pretty much anything in them. That, however, is not to say there wasn’t an ideal that most people aspired to. Good rump steak, so I was told (from a local steer, raised and butchered the way it was decades ago) was an excellent example of a “traditional” filling, mixed with a little potato and/or turnip, or course.
There are many, many other possibilities. Pork is another biggie, as is mutton (mutton pasties were by far my favorite when I lived in Devonshire). Big pieces of any of those meats would have made a prize pasty in the old days. And when I say “pieces” I mean “pieces”. No self-respecting Cornish woman would have ever put ground (or “minced”) meat in a pasty. Minced meat is for children, in their view, not for grown men and women.
As far as vegetables go, potatoes and Swedes (yellow turnips) are the classics, sometimes supplemented by cabbage or leeks, rarely carrot, I don’t know why (it’s not considered “authentic” for some reason).
And of course all ingredients must go into the unbaked pasty raw. This is critical, and one of the things that makes the pasty unique in the world of hand-held pies. All others (calzones, empanadas, samosas, pupusas, momos, pizza puffs, you name it) contain fillings that have already been cooked. Why do the Cornish do it this way? Because only the uncooked foods make “the gravy”, as any Cornish home baker would tell you. That’s good enough for me.