Preheat the oven to 180°C (gas 4). Scoop out and discard the pumpkin seeds and pulp. Place the pumpkin or sweet potato on a baking tray and rub the butter, ghee or oil and salt. Bake on the middle oven rack until tender - about 1 hour. (If you're pressed for time, cut the pumpkin or spuds into smaller chunks and bake for 20 minutes.) Scoop out the pumpkin flesh (or slip off the sweet potato skins when they've cooled) and puree using a stick blender or a potato masher. Once cool freeze in 1 cup (250ml) batches or ice-cube trays.
From Wilson, Sarah. “I Quit Sugar: Simplicious.” I Quit Sugar: Simplicious, Macmillan, 2016, p. 23.