In a large pot over medium heat, warm the cooking oil until it shimmers. Add the minced garlic, onions, and half of the tomatoes. Sauté until the onions turn translucent and the mixture becomes fragrant.
Add the beef neck bones and continue to sauté until they develop a rich brown color on the edges. Pour in the rice water and bring it to a gentle boil. Once boiling, cover the pot and reduce the heat to low. Allow it to simmer until the beef becomes tender and the broth deepens in flavor. Skim off any scum that forms on the surface using a ladle or skimmer. If necessary, add more water during the cooking process to maintain enough liquid.
Once the beef is tender, stir in the Maggi Magic Sinigang sa Sampaloc mix and beef powder. Mix well until fully dissolved. Add the taro root and daikon radish, cover again, and continue simmering until the taro turns soft and slightly creamy.
Next, add the eggplant slices, remaining tomatoes, and long green peppers. Cook for about 5 minutes to allow their flavors to blend with the broth. Season with fish sauce to your preferred saltiness.
Add the okra and string beans, then continue cooking for another 5 minutes, just until the vegetables are tender yet still slightly crisp. Finally, stir in the water spinach leaves and let them cook for about 1 minute, just enough to wilt.
Transfer the Beef Porridge to a large serving bowl. Serve hot alongside steamed rice for a hearty and comforting Filipino meal.