I've recently realized that many people I talk to have never roasted a pumpkin before. While I certainly appreciate the convenience and flexibility of canned pumpkin, I think that using fresh pumpkin is something that everyone should at least try once. I remember thinking that it must be the hardest thing in the world - turning a hard vegetable like squash into that smooth puree for pies. Once I tried it I realized how easy it really is.
Start with a pie pumpkin (or sugar pumpkin, as they are sometimes called). The only grocery store I can always count on to carry these around here is Trader Joe's. Safeway, Albertsons and the like seem to only carry other varieties of winter squash. Don't forget your local farmer's market.
Remove the stem, cut in half, scoop out the seeds and stringy bits (clean and roast the seeds if you like).
Having an orange cat around as "helper" is entirely optional.
Some people like to put their pumpkin halves cut-side down. I prefer cut-side up, so they don't stick to the foil.
After roasting at 350 degrees for an hour or so, they should be easily pierced with a fork. The time really does vary, so check and adjust.
It's best to let them sit for awhile, to prevent burning your fingers as you handle them, and then scoop out the flesh from the skins.
A quick pulse in the food processor turns it from this...
... into this. A smooth puree ready for pie, cookies, or whatever else you like to make with pumpkin.
One trick I learned for dealing with leftover pumpkin puree - measure 1-cup amounts into a sandwich size Ziploc. Smooth flat and lay in the freezer. Next time you need a cup of pumpkin puree just take out a bag and let it defrost on the counter.