Heat the oil in a heavy-based saucepan, add the onion, garlic and chillies and cook for 2–3 minutes. Stir in the turmeric, then pour in the stock and white wine. Bring to the boil, then reduce the heat and cook gently for 8–10 minutes.
Meanwhile, scrub the mussels in plenty of cold water. Scrape off any barnacles and beards with a knife and discard any mussels that fail to open when lightly tapped on a work surface. Rinse well, then drain.
Season the broth, then tip in the mussels with half the herbs and bring to the boil. Cover and cook gently for 5 minutes, or until the mussels open. Discard any that remain shut. Scatter with the remaining herbs and serve with crusty bread.