To begin, wash the pork and offal thoroughly. Drain well and cut into small cubes. Pat dry with kitchen paper to prevent excess moisture. Move on to sautéing the aromatics.
In a heavy based pot, heat oil over medium heat. Add chopped onions and sauté until soft and translucent. Follow with minced garlic and cook until fragrant. Proceed to sear the pork.
Add the pork cubes and offal to the pot. Cook for 5–7 minutes, stirring occasionally, until the meat is lightly browned on all sides. This step develops flavour for the stew. Transition to seasoning.
Stir in the fish sauce and freshly ground black pepper. Allow the seasoning to coat the meat. Add a splash of stock to deglaze the pot, scraping up any browned bits. Move to simmering.
Pour in the rest of the pork stock, bring to a gentle boil, then lower the heat. Cover and simmer for 25–30 minutes, stirring occasionally, until the pork is tender. Prepare the blood mixture while simmering.
In a bowl, mix the fresh pork blood with vinegar. Stir well to prevent clotting. This mixture will thicken the stew and create its signature flavour. Transition to adding it to the pot.
Slowly pour the blood mixture into the simmering pot while stirring continuously. Keep stirring for a few minutes to ensure the blood blends smoothly without curdling. Proceed to adding chillies.
Place the whole green chillies into the stew. Let the stew simmer gently for another 10–15 minutes until it thickens to a velvety consistency. Taste and adjust seasoning with salt if needed.
Turn off the heat and let the Dinuguan rest for 5 minutes before serving. This allows flavours to meld. Prepare garnishes and accompaniments.
Ladle Dinuguan into bowls and serve hot with steamed white rice or traditional puto (Filipino rice cakes). Garnish with additional sliced chillies for extra heat if desired.