Peel and chop the pumpkin into 1.5 cm chunks (see video link in the notes above for guidance if required). Peel and chop the onion, and wash and cut the potato into 1cm cubes.
Heat the oil in a pan over a medium heat, and fry the onion for 7-8 minutes. Add the potato and stir over the heat for a couple of minutes.
Add the pumpkin, stock, nutmeg and seasoning. Bring to the boil, cover and simmer for 15-20 minutes until the vegetables are soft.
Remove from the heat, and blitz until smooth. I use a hand blender, but you could use a food processor if you prefer. Adjust the seasoning if necessary.
Notes
Vary the spices to suit. Why not try a generous pinch of ginger, ground cinnamon and/or cardamom?
If you'd like an Asian inspired pumpkin soup, try using a can of coconut milk instead of stock, along with a generous pinch of ground cumin, coriander and ginger.