Okay, so the plural of pasty (the Cornish by way of UP of Michigan shortcrust filled with stuff dish) should probably be "pasties", but every time I say I'm making pasties my smartass friends make wisecrack remarks about sticking things to stripper's boobal regions....
Filling: Heavy on the root vegetables, onions, turnips, potatoes. I threw in some diced up celery root, which seemed to be tasty, and put in some peas and carrots because I could. Cook until soft in a little olive oil (basically, sweat the vegetables). I throw in some salt and pepper, some Bragg's, some nutritional yeast, some parsley.
Cooling: For the love of all that is good and holy, cool the filling completely before putting it in the crust. If you don't you essentially melt the crust, and that's no good.
Crust: shortcrust. Two hints here: first, stick whatever fat you're going to use in the freezer until it's nice and hard. Rummage around in your kitchen until you find that hand crank grater, you know, the one you have that's absolutely useless in grating hard cheeses? Yeah, that one. It works up a charm to grate the shortning into the flour, which makes it trivial to integrate. That trick I discovered from someone else. The second trick I came up with on my own: to add the scant amount of ice water necessary to bring the crust together, get one of those water bottles you use on bike rides (if you're a bike person like me, you've probably got a half-dozen of these things in your kitchen right now). Easy to squirt in tiny bits of water.
Crust: ... or, just buy pre-made pie crusts, the kind you have to thaw and carefully unroll to use. The only downside is that a stock piecrust is about half the thickness that you really need to hold up in a pasty; the next time I try this I'm contemplating putting down one crust, brushing some water on, putting down another, and lightly pressing them together with a rolling pin, to see how that works.
Cooling, part deux: Let them cool for a good long time, otherwise they'll fall apart.