Place a large saucepan over a medium-high heat.
Add the oil, onion, turmeric, cumin and ginger and cook for 3 minutes, stirring constantly, until soft.
Add the sweet potato, carrot, coconut milk and stock and simmer for 30-35 minutes or until the vegetables are tender.
Add the coriander, salt and pepper and stir through. Divide soup between bowls and top with sliced chilli.