In large pot, add pork fat, heart, and lungs, lemongrass, pandan leaves, 1 cup of vinegar, 1 tbsp salt, and enough water to cover the meat.
Bring to a boil and cook for 20 minutes.
Remove meat, let it cool, then dice finely. Set aside.
In a heavy frying pan, heat oil and sauté garlic and onions until translucent.
Add the chopped meat, siling labuyo (or cayenne pepper), and bay leaves. Stir fry for 3 minutes.
Add bell pepper, 1 cup of vinegar, and stock. Bring to a boil and simmer on high heat until sauce thickens.
Add more vinegar if you want a more sour taste.
Add the annatto powder mixture, then season with fish sauce and lots of freshly ground black pepper.
Simmer for 2 minutes, then place in big bell peppers and garnish with green chili pepper. Serve with hot rice.