Slice off the top of the pumpkin and scoop out the seeds/membranes.
Cut the pumpkins into quarters and place in a slow cooker.
Cover and cook on high for 4 hours or low for 6-8 hours.
Scoop the flesh out of the shell and place in the blender.
Puree the pumpkin until smooth, approximately 2-3 minutes.
Transfer the pumpkin to an airtight container and store in the refrigerator for up to 5 days.
Video
Notes
Be sure to use Pumpkin Pie Pumpkins and not the same pumpkins used for carving as they tend to be stringy. Pumpkin Puree can be frozen for up to 60 days in an airtight container.