Thai red curry paste is made from a variety of ingredients, which all add to its unique and rich flavour. The main ingredients include chilli, lemongrass, shallots, ginger, coriander, lime and shrimp paste. To make this from scratch you need a fair amount of arm strength as traditionally everything is mashed together by hand in a mortar and pestle. I'm usually pretty happy to buy a decent store-bought version though. They are perfect for curries like this and save a ton of time.