Cut a thick slice from the pak choi root
to separate the leaves. Rinse and drain.
Heat the groundnut oil in a large wok
over a medium heat and add 1 tbsp
sesame oil, the garlic, chilli, fish sauce (if
using) and pak choi. Toss until coated and
clamp a pan lid over them. Reduce the
heat and cook for 3-6 minutes, tossing
occasionally, just until the leaves have
wilted (the stalks should be tender-crisp).
Add the rest of the sesame oil and salt.
Toss the leaves and serve immediately.