Grill pork leg on a charcoal barbecue to lightly char the meat on all sides, this is needed for that smoky flavour.
In a pot add water, pork leg, batuan, lemon grass and onions, bring it to a boil then simmer for 30 minutes.
Add the pigeon peas or black beans then simmer for 30 minutes.
Add jackfruit simmer for 30 more minutes.
Add spinach and finger chillies, simmer for 5 more minutes.
Season with fish sauce or salt and freshly ground black pepper