Preheat the oven to 180ºC. Place the pumpkin chunks on a baking tray, drizzle with 1 tablespoon of olive oil and season generously with sea salt and black pepper. Bake for 40-45 minutes. When the pumpkin has about 25 minutes to go, heat the remaining olive oil and butter in a deep saucepan on a low-medium heat and cook the onions and garlic for 15 minutes until the onion starts to caramelise. Add in all the spices and cook for a further 2 minutes, then add in the coconut milk and stock. Bring to the boil, then simmer for 10 minutes. Once the pumpkin is ready, add the chunks into the soup and blitz half the soup with a blender. Keep half of the soup chunky. The soup when served can be garnish with chopped rosemary and a dollop of sour cream.