If you’re using fresh pumpkin, cut them into cubes and bake inside a pouch of aluminum foil. Make sure they are well covered. Bake for 20 minutes at 200°C until tender and you can pierce with a fork. Then measure 300 g. If using canned pumpkin, use directly.
In a food processor, blitz the pumpkin if needed. Then add all the ingredients and process further until no lumps remain.
Pour in your pre-baked pie shell (it can still be hot) and bake at 180°C in a preheated oven for about 30 minutes. The sides will seems more set than the middle but it will solidify as it cools.
Serve with whipped cream if desired, I like to eat it on its own.