Cooking Pumpkins for Puree
This is not difficult, honest!
First of all, use a small sugar pumpkin, not a carving pumpkin. Carving pumpkins are not as sweet and are stringier. Most commercial pumpkin puree is actually Blue Hubbard squash. These are quite large and generally require an ax to break them into smaller, more manageable pieces. You could go for the smaller "baby” Blue Hubbards, though, and get away with using a knife.
Assuming you've chosen the sugar pumpkin, you now have a few choices: Baking it in the oven, cooking it in a microwave, or steaming it. I usually steam it. Remove the stem using a sharp knife, preferably a carving knife, and cut the pumpkin into quarters. Scoop out the seeds and slimy pulp. Put pieces in dutch oven with a couple of inches of water. Bring water to a boil, cook for about 20 minutes, until flesh is soft. Drain. On a cutting board, scoop flesh away from the skin.
To bake in oven: Remove stem and cut in quarters. Bake on a cookie sheet for 45 minutes or so then scoop out seeds and stringy stuff. Then scoop out flesh.
To cook in microwave: Remove stem. Poke several holes in sides (if you don't do this, the pumpkin will explode) and bake on high for 30 minutes until it is soft. Cut it open, scoop out the seeds and stringy insides, and separate the flesh from the skin.
To use the flesh in a recipe you will want to mash the flesh well, or puree it in a blender or food processor. A pumpkin that is 7 to 8 inches in diameter will yield approximately 2 cups of pumpkin, which is enough for one pumpkin pie.