In a large pan over a medium heat, fry the Thai base for 1-2 minutes until fragrant. Pour in the coconut milk and 100ml water and bring to the boil. Reduce to a simmer and cook for 2 minutes.
Add the chillies, zest and juice of two limes, mirin, pack choi and mussels. Cover with a tight-fitting lid and cook for 3-4 minutes, or until the mussels open. Discard any mussels that remain shut.
Garnish the mussels with the coriander and serve with the bread and wedges of lime on the side.
Cook’s tip: halfway through cooking time, use a long handled cooking spoon to carefully stir the mussels in the saucepan. This will make sure that all of the mussels cook in the same length of time