Here is my recipe.
Put some black mustard seeds into sesame oil. Once they start to pop, put in some onions, garlic, grated ginger and finely chopped lemongrass. when the onions turn golden add plenty of red and green peppers and a couple of chopped chillies. then add some aubergine..........very important for me, they soak up all the flavours and oils.
Then add the chiken/prawns and a bit of thai curry paste. when the chicken is on its way you can add a tin of coconut milk. Don't worry if it's not green and it tastes too coconuty at this stage, the flavours need to infuse.
Chop some thai basil leaves and kafir lime leaves and add them. Squeeze in half a lime (stick the other half in a G&T) and add 1 tsp of thai fish sauce (V. important, this really gives it the authentic taste and means you MUST NOT ADD EXTRA SALT). Add a little palm sugar or 1/2 tsp of brown sugar if you don't have any.
Finally, the best bit, stir in a generous helping of fresh corriander and serve with thai jasmine rice.
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OR:
The quick version.......
fry some chicken, add plenty of thai curry paste, add coconut milk and serve.
but if you have time and access to asian supermarkets it's worth the extra effort