Note Coconut oil is available in jars from select delicatessens and health-food shops. To roast shrimp paste, wrap it in foil and roast at 180C until fragrant (15 minutes).
This recipe requires a bit of preparation, but it can all be done in advance. In fact, you can cook the curry the day before you plan to serve it, because the flavours will only get better with time. If time is tight you could buy a good-quality curry paste, such as Mae Ploy; you'll need about 60gm, plus a little extra fresh turmeric for colour. But shop-bought pastes tend to be quite salty, so be wary of over-seasoning the curry with fish sauce. The roti is adapted from a recipe in David Thompson's Thai Street Food. You'll need to prepare the roti dough a day ahead, but roll and cook it just before your guests arrive and warm it in the oven just before serving.