Put the lemongrass, kaffir lime leaves, chilli, ginger, garlic, turmeric, pinch of brown sugar, fish sauce, zest and juice of lime into a mini blender and whizz together, add 2 tablespoons of water and blend to a paste.
Transfer the paste and the coconut milk in to a large saucepan and cook on a low-medium heat for 5 minutes.
Add the mussels into the sauce, cover and cook over a medium-high heat for 4-5 minutes, shaking the saucepan a few times until the mussels have opened. Discard any that have not opened.
To serve, top with coriander and scallions and serve with bread.