Making your own purée has benefits: It's fresher, and you can roast the pumpkin into a darker, sweeter flavor. Plus you have all those seeds to roast and eat too!
First you'll roast the pumpkin, then you'll purée the flesh. This will last for a few days in the fridge, or a few months in the freezer. Here's how to do it.
How To Make Fresh Homemade Pumpkin Purée from Scratch
What You Need
Chef's knife and cutting board
Food processor or food mill
Split the pumpkin and then scrape out the seeds. Scrape the seeds and attached strings out of your split pumpkin. Don't throw these away! If you don't have time to deal with them now, however, you can cover the bowl and refrigerate for several days.
Roast until soft and then scrape up the flesh. Heat the oven to 400°F. Place the two halves cut-side up in a baking dish and roast for about an hour or until very soft inside. Remove from the oven and let cool. Scrape up all the flesh inside the pumpkin, leaving only an empty shell or rind behind. If there is a lot of thick flesh that is too hard to be scraped up, then the pumpkin needs to roast longer. Scrape up all the flesh inside the pumpkin, leaving only an empty shell or rind behind. If there is a lot of thick flesh that is too hard to be scraped up, then the pumpkin needs to roast longer.
Purée until smooth. Put all that scraped-up pumpkin in a food processor or food mill and purée until smooth. Refrigerate immediately; this will last for a few days in the fridge or a couple months in the freezer, well-sealed. When you take it out to use it, you will probably notice some water separation. Make sure to drain this water away before using it in a recipe!