Heat the oven to 400 degrees F.
Slice a small piece of skin off one side of the pumpkin so when laid on its side, the pumpkin will lay flat without rolling. Remove stem & split the pumpkin in half from top to bottom, using a large cleaver & a mallet. Scoop out the seeds & fiber with a large metal spoon. Reserve seeds for another use.
Sprinkle the flesh with kosher salt & lay the halves, flesh side down, on a parchment paper-lined pan. Roast until a paring knife can be easily inserted & removed from the pumpkin, 30 to 45 minutes. Test in several places to ensure doneness.
Remove pan to a cooling rack & cool the pumpkin for 1 hour. Using a large spoon, remove the roasted flesh of the pumpkin from the skin to the bowl of a food processor. Process until the flesh is smooth, 3 to 4 minutes. Store in the fridge for up to 1 week or freeze for up to 3 months.