Pre heat your oven to 190C. Cut your butternut squash in half and place on a baking tray. Add fresh thyme, chilli flakes, salt, black pepper and drizzle with olive oil. Roast in the oven for 30 minutes.
After 30 minutes, remove from the oven and add the garlic bulb and onion. Roast for another 30 minutes, or until the butternut squash is soft.
Remove from the oven and use a spoon to remove the flesh from the butternut squash. Place in a food processor or blender with the cooked onion and squeeze out the content of the roasted garlic. Add the double cream and vegetable stock to the blender and blend until fully combined (add more vegetable stock if needed).