If you don't have fresh turmeric, substitute 2-3 teaspoons ground turmeric. I grate all of these ingredients on a Microplane grater. Feel free to smash the ingredients in a mortar and pestle, or whiz them together in a food processor or blender. It will achieve the same end result, so do what works for you. You can buy shrimp paste (Belacan) from specialist Asian supermarkets. If you can't find it, leave it out. The dish will still be good. I serve this with a noodle salad.