Combine all the ingredients in a blender, whiz until nearly smooth. Pour into a small saucepan, and bring to the boil. Reduce heat and simmer for about 5 minutes, stirring frequently, until slightly thickened.
Serve cold, room temperature, or hot -- depending on what you are using it for, as a sauce or a condiment.
Notes
If no fresh coriander is to hand, try fresh parsley, or dried parsley. Makes 1 cup / 8 oz / 250ml.