1: Remove the skin and seeds from the pumpkin and discard. Dice the flesh into 3cm chunks.
2: In a large heavy bottomed pan, heat a little of the oil and melt 25g of the butter.
3: Add the chopped onion and a pinch of salt. Sweat down until soft and then add the dried mushrooms and cook for a further 5 minutes until the mushrooms have softened and released some flavour.
4: Add the chunks of pumpkin and pour on the chicken stock. Turn the heat up and bring to the boil. Turn the heat down to a gentle simmer and cook until the pumpkin is soft. This will take about 40 minutes.
5: Pour in the double cream and bring to the boil. Remove the pan from the heat and blend the soup in a jug blender until smooth. You may not need all of the liquid so add it a bit at a time or the soup may be too loose. When blended, pass the soup through a fine sieve, season and keep until needed.
6: In a pre-heated oven at 180°C, place the pumpkin seeds in a dry tray and toast them for 5-8 minutes until a little tinged. Remove and keep as a garnish.
7: Fry the oyster mushrooms in a pan with the remaining butter and season. When cooked, place them in the bottom of 4 soup bowls. Crumble on the blue cheese. Heat up the soup and pour on top of the cheese and mushrooms. Sprinkle with the toasted pumpkin seeds and drizzle on the pumpkin oil and serve.