In a sauce pan heat up a couple of tablespoons of olive oil along with the butter.
Once the butter starts to foam add the chopped onion, celery stalk and carrot and fry for 5-10 minutes, until the onion turns translucent. Now add the potatoes and after 2 minutes the pumpkin into the saucepan. Fry all together for the next 5 minutes or so, give it a stir and cover with the stock.
The stock should just cover the vegetables (for a rich creamy soup).
Cook on a low heat with the lid on until the vegetables turn very soft, it should take about 25-30 minutes.
Take the pan off the heat and puree the soup until it turns creamy making sure there are no lumps left.
Pour it back into the saucepan and gently cook for another 5-10 minutes whilst adding some cinnamon, nutmeg and salt to your liking.
Serve with a drizzle of olive oil, a pinch of black pepper and some lovely crunchy bread on the side.