When I want pumpkin puree, I buy a whole sugar pumpkin at the farmer’s market. The huge pumpkins you see around Halloween time are field pumpkins and are not for eating.
Treat it like a squash. Sugar pumpkins are small and will fit into a home oven. I rub the exterior skin with a little vegetable oil, wrap the whole pumpkin in foil and place in a 350 degree oven on a baking sheet until it’s soft. Let it cool, then the skin will peel off easily. Open it up and remove the seeds.
The baked pulp will be a perfect puree, but I sometimes drain it in a sieve over a bowl to remove excess moisture.