In a bowl, add pork liver, vinegar, chopped garlic, and ground black pepper. Stir and set aside.
In a deep pan or pot, heat 1 tbsp oil over medium heat. Add the pork lungs and cook until deep brown then set aside.
Using the same pan in medium heat add 2 tbsp cooking oil. Saute the onion and garlic until onion is translucent.
Tip in slices of pork shoulder and cook until light brown in color or half-cooked. Add the cooked pork lungs mix in with the other ingredients.
Pour fish sauce and stir, simmer for a couple of seconds then add the bay leaves, pepper and water. Give it a quick stir then simmer until the pork is soft and tender. NOTE: add more water if the pork meat is still hard.
Throw in the marinated liver together with the vinegar mixture. Spread the liver using a fork but do not stir and don’t cover. Let it simmer until the aroma of vinegar evaporates approx. 10 - 15 mins.
When the liver is soft and tender, taste and adjust with fish sauce or salt. Transfer in a serving dish and serve with rice. Bon appetit!