Preheat oven to 375 degrees.
Slice the pumpkin in half, crosswise through the stem, and scoop out the seeds and strings.
Place halves, cut-side down, onto a baking sheet lined with aluminum foil.
Roast, uncovered, for 40-60 minutes, or until tender.
Remove from oven and allow to cool enough to handle. When cool, carefully scrape flesh from skin. Discard the skin.
Using a food processor or blender, puree until even and smooth.
Refrigerated leftover pumpkin puree will last about 4-6 days in the refrigerator if kept in an airtight container.