Heat the sunflower oil in a large saucepan. Stir in the onion and celery, and sauté over high heat for 3-5 minutes, until softened. Add garlic, cumin, turmeric, and chili powder and sauté, stirring until fragrant, less than a minute. Pour the stock into the pot, then add the parsnips. Sprinkle with salt and pepper. Bring to a boil, then lower the heat to medium-low and simmer, covered, for 15-20 minutes, until the parsnips are tender.
In a blender, purée the soup in small batches until smooth. Return soup to the pot and heat through. Serve with a drizzle of good olive oil in each bowl.