Preheat the oven to 400°F and line a baking sheet with parchment paper. Slice the squash in half, scoop out the seeds and place cut side down on the baking sheet.

Roast for 40 to 60 minutes or until the flesh is soft and a fork easily slides in. Let cool for about 1 hour. Use your hands to peel the flesh from the skin and place in a food processor. Puree until smooth, letting your food processor run for about a minute, stopping to scrape down the sides as needed. If your puree is more watery than the texture of canned pumpkin, strain the excess liquid by letting it sit in a fine mesh strainer (or cheesecloth) over a bowl for 30 minutes.

Chill until ready to use.