Heat a wok until smoking. Add the oil and then add the lemongrass, ginger, garlic and chilli. Stir fry for a minute or so and then add the spices.
Add the beef and stir fry to coat in all the flavours- keep the heat high, don’t let the beef ‘stew’. Next add the mushrooms and fry for a few minutes. Then add the coconut milk, mix well and simmer for 1-2 minutes. Add the seasoning ingredients and taste. You should get a balance between sweet, salty, hot and sour. Adjust seasoning if necessary.
Just before serving, add the basil leaves and mix through. Sprinkle over the coriander and serve with steamed rice.
Options: You could add spinach or green beans instead of or as well as the mushrooms.