Using fresh coriander roots is the key to this recipe because they retain their fragrance much more than the leaves during cooking. This amazing marinade is equally delicious with roasted or grilled chicken recipes.
Wash and pat dry the filets.
Chop the lemongrass and roughly grind in a mortar. Add garlic, green pepper and coriander roots with salt and grind to a paste. Incorporate the sugar and fish sauce.
Rub the paste thoroughly on the fish filets. Let rest for 30 minutes, time permitting.
Grill the fish for 7 minutes on a grill or for 10 minutes in a 450 °F oven. Meanwhile, prepare the dip. Put the sugar and vinegar in a pan and bring to a boil. Add the pepper. Mix and transfer to a bowl. Serve as a side or pour over the fish.