To be honest, Regency folk weren’t baking pumpkin pies of the kind we’re used to. Pumpkin pies then were either like apple pies with roast pumpkin mixed in or pumpkins with a hole cut in them that were filled with apples, etc. and baked whole. They sound very different from what we eat now, although the spices seem similar (except I suspect none of us would put thyme, rosemary, and marjoram in our pumpkin pies). Pumpkin pie as we know it was an American dish, although it has now been incorporated into English holidays, too. I could find very few references to pumpkin pie in cookbooks of the period, although the English did use pumpkin in stews and soups. The Scottish, on the other hand, did cook pumpkin in ways similar to ours—like a custard or pudding. Perhaps that’s where we got it from—plenty of Scots emigrated to the U.S. in the early 1800’s. If you’d like to read a Scottish recipe, there’s one here for Pumpkin Pudding.