Heat cooking oil in a pan over medium heat. Sauté onions, garlic, and ginger until fragrant and onions are translucent.
Add the thinly sliced pork belly to the pan. Cook until the pork is lightly browned and cooked through.
Stir in the shrimp paste (bagoong) and cook for a few minutes to allow the flavors to meld.
Pour in the coconut milk and stir well to combine with the pork and aromatics. Let it simmer for about 10-15 minutes, stirring occasionally, until the sauce thickens slightly.
Add the sliced long green chili peppers (siling pansigang) and chopped red chili peppers (siling labuyo) to the pan. Adjust the amount of red chili peppers according to your desired level of spiciness.
Allow the dish to simmer for another 5-7 minutes, or until the chili peppers are tender and the flavors have melded together.
Taste the Bicol Express and season with salt and pepper as needed. Adjust the seasoning according to your preference.
Transfer the Bicol Express to a serving dish and serve hot with steamed rice.
Leftover Bicol Express can be stored in an airtight container in the refrigerator for up to 3 days. Reheat gently on the stove or in the microwave before serving.
Bicol Express can also be made with other proteins such as chicken, shrimp, or tofu for a vegetarian option. You can also add vegetables like string beans (sitaw) or spinach to add more texture and color to the dish.