stirring, reduce heat to medium and add chicken, remaining coconut milk, ginger slices and lemon grass. Bring to boil, reduce heat, and simmer uncovered until chicken is tender. Season with chilies, fish sauce and lime juice. Decorate servings with lime leaves and coriander sprigs. To make coconut milk: Blend 2 cups fresh or frozen grated coconut with water. Strain through double cheesecloth, pressing out all liquid. This is thick coconut milk. To get hin milk, add warm water to residue from first straining. Let stand 5 minutes, then press as before. For coconut cream, refrigerate first pressing and cream will rise to top. Refrigerate or freeze. Two cups coconut makes 3 cups thick milk, of which 6 tablespoons is cream.