In a blender add the lemongrass, coriander stalks and stems, shallots, ginger, turmeric, dried chili, garlic and water. Blend until a rough paste is formed. Add a little extra water if necessary to aid the process. 

Place a small amount of oil in a large frypan and add the chili paste. Cook on a low heat until the paste is sizzling and well cooked. Add the coconut cream and stir well. Bring to a simmer and allow to cook for a further five minutes to develop flavour. 

Add salt to taste and the sugar if you feel its needs to be sweetened slightly and add the juice of half a lime.

While the curry is cooking, chop the fish fillets into large pieces approx 1inch square. Add these to the cooked out curry sauce and cook on medium heat for three or four minutes to cook the fish through. Once turned off the residual heat will continue to cook the fish slightly.

Serve with steamed jasmine rice and top with coriander leaves to garnish.