Pumpkin puree is one of the easiest things to make from scratch. You can replace your canned pumpkin with pumpkins fresh from your garden, and it hardly takes any effort at all. The best kind of pumpkins are sugar or pie pumpkins, so buy or grow those if you want a nice smooth puree. Carving pumpkins are stringy and not as yummy.
I’ve attempted to grow pumpkins in the garden for about three years straight now, and I always start them too late. Last year I actually got one tiny little pumpkin and we roasted it, but I also do this with pumpkins from the store, or even homegrown butternut, acorn, or spaghetti squash. If you don’t have any pumpkin and you are in dire need of a pumpkin pie butternut squash makes an awesome substitute, and you cook it exactly the same way.