Place a rack in the middle of the oven and preheat to 400°F.
Cut the pumpkin in half from top to bottom and scoop out the seeds and pulp with a spoon. It can help to cut off the stem first before cutting the pumpkin in half.
Segment the clean pumpkins into thick 3 or 4 inch slices.
Lightly oil the pumpkins and place them skin side down on the baking sheet.
Roast the pumpkin segments in the oven for 45 minutes to an hour, or until the pumpkins are soft when poked with a fork.
Remove the pumpkin from the oven and let it cool before removing the peel and scooping out the roasted pumpkin with a spoon. Once roasted, the pumpkin can be eaten as is, or pureed.
To puree roasted pumpkin, transfer to a blender or food processor and blend until smooth. Freeze extra pumpkin puree to save for later.