Cut a thin layer off the top and bottom of your pumpkin. Then cut the pumpkin in half, scoop out the seeds and pulp and strings and discard.
Cut the pumpkin into small 1 to 2-inch chunks. Then trim off the outer skin and discard.
Fill a stockpot with 1-inch of water. Place the peeled pumpkin chunks in the stockpot (fill the pumpkin up as much as you want). Cover and cook for approximately 30 minutes (or until soft) on medium-heat.
Pour the cooked pumpkin and water into a large mixing bowl, and mash. It's easiest to use a blender or a food processor, if you have one. Use short bursts to puree so you don't liquefy it (you want it to be kind of chunky).
Use the pumpkin right away, or freeze it in 1 cup containers.