1. In a wok, heat the vegetable oil.
2. Add the garlic and saute it.
3. Throw in the onions and saute everything together.
4. Add the chopped tomatoes and cook for a while and let them soften.Mash the tomatoes with the spatula.
5. Pour in the fish sauce.
6. Empty the ground beef in the wok and mix it in.
7. Saute in high heat and addd the freshly ground black pepper.Cover and let it simmer for a few minutes.
8. Add the green chilies and the bitter melon. Cover and cook.
9. Ladle it on steamed white rice and serve right away.