Pat the pork belly dry with paper towels and cut into evenly sized 1-inch cubes. Finely chop the onion, mince the garlic and ginger, and slice the green and red chilies. Wear gloves if you are sensitive to chili oils and avoid touching your face.

Heat a large heavy-bottomed pot or deep skillet over medium heat. Add the neutral oil, then add the pork belly pieces in a single layer, working in batches if necessary. Let the pork render and lightly brown, stirring occasionally, for about 10–12 minutes until you see golden edges. Spoon off excess fat if there is a lot, leaving about 1–2 tablespoons in the pan.

Push the pork to one side of the pot or transfer it briefly to a plate. In the same pot with the rendered fat, add the chopped onion and cook over medium heat for 3–4 minutes until soft and translucent. Add the garlic and ginger and sauté for 1–2 minutes more, stirring often, until fragrant but not burnt. Lower the heat if anything browns too quickly.

Add the shrimp paste (bagoong alamang) to the pot and cook for 2–3 minutes, stirring and pressing it into the aromatics. This mellows the sharpness of the shrimp paste and develops its flavor. It will smell strong at first but will balance once the coconut milk is added.

Return the pork (and any accumulated juices) to the pot if you removed it. Stir well so the pork is coated with the aromatic-shrimp paste mixture. Cook together for another 2–3 minutes to start blending the flavors.

Pour in the coconut milk and stir, scraping up any browned bits from the bottom of the pan. Bring to a gentle simmer over medium heat, avoiding a hard boil to prevent the coconut milk from separating. Once simmering, reduce the heat to medium-low.

Stir in the long green chilies and about half of the red bird’s eye chilies. Add the ground black pepper, 1 teaspoon of fish sauce, and 1 teaspoon of brown sugar if using. Simmer uncovered for 20–25 minutes, stirring occasionally, until the pork is tender and the sauce begins to thicken.

Pour in the coconut cream and stir well. Continue to simmer for another 10–15 minutes, or until the sauce is thick, glossy, and clings to the pork. Taste and adjust: add more fish sauce for salt, more chilies for heat, or a pinch of brown sugar if the flavors seem too sharp or salty. If the sauce is too thick, add a splash of water or extra coconut milk; if too thin, simmer a bit longer.

Turn off the heat and let the Bicol Express rest for about 5 minutes to allow the sauce to settle and thicken slightly. Garnish with extra sliced chilies, chopped green onions, or a squeeze of calamansi or lime, if desired.

Serve hot over steamed white rice, garlic fried rice, or cauliflower rice for a low-carb option. Spoon plenty of the creamy, spicy coconut sauce over the pork when serving.