How to make it
Scratch the ginger and remove the skin. Crush the ginger with the back of a knife. On a wok over low heat, fry the ginger until moisture evaporates. Add oil and fry until ginger becomes fragrant. Set aside.
Cook through the salted egg and remove the shell. Soak the wood ear mushrooms until soft. Blanch for 5 minutes. Drain well.
Bring vinegar to boil in a big clay pot. Turn into medium high heat. Add ginger. Turn into low heat and boil for 10 minutes. Turn off the heat and let cool. Keep it in dry and cool place or in the fridge for a few days to let the ginger absorb the sauce.
Shave the pork knuckle. Put into boiling water and blanch for 20 minutes. Drain well and set aside.
Take the ginger out from the fridge. Rest in room temperature. Bring to boil and add pork knuckle. Turn into lower heat and boil for about1½ houruntil the pork is tender.
Add salted egg and wood ear mushroom into the vinegar. Bring to boil and turn off the heat immediately. Poach the salted eggs for about 3 hours until colored. Warm it up again before serving.
It tastes more delicious when cook in a clay pot.