Rinse the beans thoroughly under cold running water until the water runs clear. Drain thoroughly.
If presoaking mung beans: In a deep pan, pour water over the beans about¾ of the pan. Let it soak for at least 3 hours or preferably overnight.
In a deep pan, pour water over the beans about ¾ of the pan. Bring to a boil over medium heat, scraping off any foam that rises to the top
Reduce the heat to low, cover, and simmer for about 40 minutes to an hour (this can be less using pre-soaked beans), or until the beans have softened and the skins have burst. Add more water as needed to keep enough liquid.
Optional: If you want a thick soup, you can mash the mung beans at this point as they are softened. Using the back of your spoon, mash the beans against the side of the pan. Do this until you reach your desired consistency.
In a separate saucepan over medium heat, add the oil. Sauté garlic and onion until soft and fragrant.
Add chicken and cook meat turns white in color and slightly cooked, around 3-5 minutes.
Put-in celery, tomatoes, fish sauce and ground black pepper. Continue to cook until the tomatoes releases its juices and can be easily mash, around 3 minutes. Mix while smashing the tomatoes with the back of the spoon.
Pour enough water to cover the chicken and simmer for 10 minutes or until chicken meat gets tender.
Add the cooked munggo and stir to incorporate. Reduce the heat to low and simmer for about 5 minutes. Add water if it is too thick.
Combine the malunggay leaves and mix well. Taste and season with salt and ground black pepper as needed.
Turnoff the heat and cover the pan for 1 to 2 minutes to cook the leaves with the remaining heat.
Serve with rice while hot.
Share and enjoy!