I don't know where this pie recipe comes from originally but my great-grandmother made it. I suspect it was a way of "doing without" pastry flour. We like it.
Heavily butter a pie pan and coat it with cornmeal. Fill with your pumpkin pie filling & bake. That's it. The cornmeal seals the outside of the custard so that you can cut it in slices like pie but there is no pastry.