Start by prepping all the ingredients. Mince the garlic, chop the onion, slice the pork belly into thin strips, and trim the kangkong, keeping the leaves and tender stalks.

In a large pan, heat 2 tablespoons of cooking oil over medium heat. Add the sliced pork belly to the pan. Cook, stirring occasionally, until the pork starts to brown and its fat begins to render, about 5–7 minutes.

Add the minced garlic and chopped onion. Sauté until the garlic is golden brown and the onion is softened and translucent.

Pour in 2 tablespoons of oyster sauce, 1/4 cup of soy sauce, 1/2 cup of water, and 1/2 cup of vinegar. Let it simmer.

Add 1 tablespoon of brown sugar, and 1 teaspoon of black pepper powder. Mix everything well.

Lower the heat, cover the pan, and let it simmer for about 10–12 minutes until the pork is tender and the sauce has slightly thickened.

Add the kangkong leaves and tender stalks to the pan. Toss gently to coat with the sauce, and cook for 2–3 minutes until the kangkong is just wilted but still vibrant.

Taste the sauce and adjust if needed (you can add a bit more soy sauce or brown sugar to your preference).