Remove the stem and rinse the pumpkin. Slice the pumpkin in half from top to bottom. Remove all the seeds and stringy fiber from inside the pumpkin and discard or save the seeds for another use.
Sprinkle the inside on the pumpkin halves with a little kosher salt then lay them on a baking sheet lined with parchment paper cut side down.
Roast in the oven until tender, about 30 minutes.
Remove the pumpkin halves from the oven and place on a cooling rack. Allow to cool about 30 minutes.
Scoop the flesh out from the pumpkin and puree in a food processor until smooth.
If necessary, transfer pumpkin puree to a cheesecloth to drain off any excess liquid.
You can now use your pumpkin puree or store in an air tight container in the refrigerator for up to 3 days. Makes about 2 cups of pumpkin puree.