Preheat oven to 400 degrees.

Wash the exterior of the pumpkin and set it on a baking sheet with sides. Spear the pumpkin through to the center a few times with a sharp knife so the steam can release as it cooks.

Roast the pumpkin until tender enough to easily spear with a knife. When it's done, it should feel as tender as spearing a fresh peach.  Cooking time will vary depending on the size of the pumpkin, but will likely start at about an hour and go up from there.

Leave it to cool enough to handle. Cut half. Scoop out the seeds and string. Scrape the flesh from the pumpkin skin into a blender or food processor and puree until smooth.

If you're planning to use the puree for pie or baked goods, assess if it is thick enough. It should be similar to what you find in canned pumpkin. If there is too much liquid, put it in a fine mesh sieve set over a bowl and leave it in the fridge for several hours or overnight to drain You could also line an ordinary colander with cheese cloth if you don't have a fine strainer. You can save the liquid to use in place of broth in pumpkin soup.

Store the pumpkin puree in a covered container in the fridge and use within one week or freeze for up to three months.