Wash fruit, peel, and cut in half. Remove seeds and strings and cut into slices or cubes. Steam or boil until tender. Mash. Cool and pack into rigid containers, leaving 1/2 to 1 inch headspace, and freeze. Prepared this way, pumpkin will last up to one year in the freezer. Thaw frozen pumpkin in the top of a double boiler, season and serve as a vegetable or thaw in the fridge and use to make a pumpkin pie or pumpkin soup.
Fresh pumpkin contains a high percentage of water, and it may need to be cooked down to achieve the consistency of canned pumpkin pulp. Steamed or baked pumpkin can be heated to a simmer and stirred occasionally until some of the water is cooked away. It can also be wrapped in cheesecloth and set over a bowl for several hours to drain.