Heat a little oil in a frying pan. Season the hake and add to the pan, flesh side down. Cook for 4-5 minutes on each side until the fish flakes easily.
Make the sauce while the fish is cooking. Put the water, butter, sweet chilli sauce and ginger in a separate saucepan. Bring to the boil.
Add the scallions and lime juice and simmer for 2 minutes. Just before serving add the coriander leaves.
Remove the hake to serving plates and spoon the sauce over it.
Rice or potatoes and pak choi stir-fried with chopped garlic and ginger