Preheat the oven to 200 C, 400 F, Gas Mark 6. Place the cubes of butternut squash in a roasting tray, dot with the butter and drizzle with 1 tablespoon of the olive oil. Season with salt and freshly ground black pepper and cook in the preheated oven for 30 minutes until tender. Heat the remaining tablespoon of oil in a large heavy based saucepan, stir in the onion, garlic, celery, carrot, chillies and thyme and gently fry for 5-10 minutes until softened but not browned. Stir in the butternut squash and add the stock with seasoning to taste. Cover and simmer for 25 minutes. Puree the soup in a liquidiser or food processor until thick and smooth. Return to a clean saucepan and gently heat through. Stir the spices into the lightly whipped cream and serve the soup garnished with a spoonful of cream. Sprinkle over freshly chopped coriander leaves and ground black pepper. Notes Serve with remaining spiced cream and hot crusty bread. NOTES : A hot soup with the delicious sweet flavour of butternut squash which has been roasted.