The best way I have found is to get a butter-nut pumpkin (just cut in half, leave the skin on), scrap out the seeds, drizzle oil over it and roast in a 230c oven with an onion and garlic for an hour.
Then you scrape out the roast pumpkin, squeeze out the onion and garlic. I use a stick blender with a bit of chicken stock to blend it all up. Add as much chicken stock as you think (I add 4 cups) then 2 cups of milk and let it simmer for ages (until it gets thick)
Serve with a dollop of sour cream!

