The Basic Recipe
1 can pumpkin
cinnamon, ginger, nutmeg, cloves, salt
2-3 eggs
some sweetener
some milky liquid
pie crust (bottom crust only)
Add everything in order, mix well, put it in the crust, and bake it at around 375 F for 40-60 minutes, or until a knife stuck in the middle comes out clean.
Details and Variations
As a substitute for canned pumpkin, you can use canned sweet potato (which I prefer), or you can pre-cook a squash or a couple of sweet potatoes. (Technically, the white and orange ones are all sweet potatoes, but the orange ones are often called yams.) To bake a squash, cut it in half or smaller, take out the seeds and strings, and put the halves face down in a glass pan with water in the bottom. I recommend a long slow cook, maybe 300 degrees for 90 minutes. Squash for pie should be thoroughly soft and wet. If you have a pressure cooker, you can cook squash or sweet potatoes much faster and more efficiently, except you lose some of the flavor in the water.
I've heard that canned pumpkin is really some kind of squash, and that sounds like a good idea. I've tried baking "sugar pumpkin" several times and it's always tough and bland compared to acorn or butternut squash. And jack-o-lantern pumpkins are much worse!
If you want to roast the seeds, you don't have to get fancy. I don't even rinse them. I just pick the strings out, leave some orange slimy stuff on them, mix some salt in with my fingers, spread them on a pan, and bake them at about 250F, checking them and mixing them up until they're just starting to turn brown.
Mix the spices into the pumpkin first, because it's easier to get the lumps out than if you add them later. I wrote them in order of most to least, and it's hard to go wrong on the quantities, except keep the nutmeg down or it will make the pie too bitter. If you have fresh ginger and a good garlic press, that's better than powdered ginger. Salt is important to help the eggs firm up.
Eggs are important for texture. Without them the pie will have a slimy gaggy consistency that is often marketed as "creamy". With eggs you'll get a lighter custardy texture. There must be some vegan substitutes that will work, but I haven't experimented to find out which ones are good.
For sweetener I might use a few tablespoons each of coconut sugar and molasses. Don't measure -- go by taste. You could also use real maple syrup or barley malt or brown rice sweetener or honey or even white sugar.
It's all toxic but your liver can deal with it in moderation, especially if you eat it with fiber.
I use the phrase "milky liquid" because many things will work. Most recipes call for either canned evaporated milk or sweetened condensed milk, which are expensive, unnecessary, and didn't even exist when pumpkin pie was invented. Good whole milk will work best with the eggs to make a good texture, but you could also try whipping cream, ice cream, rice milk, almond milk, or even water. If you're using a liquid sweetener, you might not need any additional liquid. Or you could experiment with a dry thick filling and see how it comes out.
(public domain, last updated November 2014)