1. Firstly, the cashews must be prepared for the cashew cream. Combine the cashews and water in a small bowl and set aside to soak for around 1 hour.
2. In the oven, place a rack in the centre and upper third section, preheating to 400F/200C. Take two baking sheets and lightly drizzle with olive oil, setting aside.
3. Slicing the pumpkins in half, use a spoon to scrape out all of the strings and seeds. The seeds should be rinsed and saved for roasting.
4. Place the pumpkins so that the scraped flesh is facing upwards and drizzle each half with salt, olive oil and the crushed red pepper flakes. Allow to roast in the oven for 30-40 minutes until soft and when a fork is inserted into the flesh, there is no resistance.
5. Take out of the oven and allow to rest until it’s cool enough to touch. Scoop out the soft pumpkin flesh with the skin, measuring 4 cups into a medium sized bowl. Set this aside.
6. In a large pot, heat the olive oil over a medium heat. Add the onions and cook until it’s browned and translucent, which should take about 7 minutes. Add the garlic and cook for one minute more. Add the curry powder and cook for 1 minute. Add 4 cups of pumpkin flesh and stir until it’s been fully mixed in.
7. Add the vegetable broth to the mixture and combine. Bring the soup to the boil and then simmer for 20 minutes. Take away from the heat and use an immersion blender until the soup becomes creamy. If you don’t have an immersion blender, just add the soup to the blender until its smooth. This can be done in several batches if necessary.
7. The final step is to create the cashew cream. Combine the cashews and its soaking water in a blender, blending for 1 minute until smooth. This should be added to the blended pumpkin soup and stirred in.
8. Add sea salt and pepper to taste. Serve with a drizzle of olive oil and sage leaves, sauteed lightly.