For the sauce: In a bowl, blend the coconut milk, coconut flakes, chili sauce, corn syrup, parsley, tomato paste, salt and lime juice and allow to marinate for 30 minutes. Then pour through a sieve or strainer into a saucepan. Heat over low heat until warmed. Whisk in the butter off the heat before serving.
For the fish: Preheat the grill to 350 degrees F or a grill pan over high heat. Then sprinkle the fish with salt, pepper and the coriander. Cook the fish on both sides until medium-well in temperature, 5 to 6 minutes per side. Once cooked, remove from the heat and rest for 2 to 3 minutes.
Serve the fish over jasmine rice. Finish with the sauce.