Most pumpkin recipes specify that canned pumpkin can be substituted for fresh, and occasionally you will find a recipe suggesting the use of fresh pumpkin as a substitute for canned. What is usually missing is the method of producing equivalent amounts. As you expand your cooking repertoire, as the new farmer's market beckons or as your child becomes curious about how food travels from farm to table, you can convert fresh pumpkin to the canned equivalent with a little time and simple equipment.
Wash pumpkin and cut in half with large knife. Remove and discard stem, outside peel and seeds, scraping pumpkin flesh free of stringy membranes with spoon.
Cut peeled pumpkin into thin slices (1/2 inch) and again into 1-inch chunks. This may seem like a lot of cutting, but one of the differences between fresh and canned pumpkin is stringiness. Chopping fresh pumpkin in small pieces reduces stringiness when cooked.
Measure pumpkin chunks for your recipe. Allow 2 generous cups of fresh pumpkin for each cup of canned pumpkin specified.
Steam pumpkin chunks in vegetable steamer until fork-tender. (If you do not have a steamer, place 1/4 cup water in the bottom of a small, covered casserole, seal the cover tight and oven-steam your pumpkin.)
Drain pumpkin thoroughly and cool chunks until you can handle them. Place in a bowl and mash or puree in a food processor. Your puree should be almost as thick as mashed potatoes to substitute cup-for-cup for canned pumpkin. If puree is noticeably watery, place twice as much as you need in a heavy-bottomed saucepan and simmer, stirring, to reduce excess liquid.
Measure puree for your recipe. Measure and freeze any remaining puree for future recipes.