Kare-Kare or Ox Tail w/ Peanut Sauce Recipe (filipino)

Ingredients:
Ox Tail
2 lbs ox tail
1 lb beef round or short ribs
Sea salt
2 large onions
2 medium carrots
1 stick celery
8 cups water
Sauce and Vegetables
2 ½ cups whole peanuts
1/3 cup Jasmine rice
2 onions
4 tbsp annatto oil (please see note)
2 Japanese eggplants
¼ bundle string beans
1 piece of banana bud/heart
6 calamansi
To Serve
2 garlic cloves
1 shallot
1/3 cup bagoong (fermented shrimp paste)
Method:
To cook the meat, heat a large Dutch oven or deep frying pan over medium-high heat. Then season the meat on all sides with salt. Add the oil to the pan and brown the meat. While the meat is browning, peel and roughly chop the onions, carrots and celery. When the meat has browned on both sides, transfer to a plate and set aside. Add the onions, carrots and celery. Sprinkle with a bit of salt and brown. Once golden, add the seared beef back to the pan. Cover the ingredients with water or just enough to cover the meat. Bring the mixture to a simmer. Lower the heat, cover and cook for about 3 to 5 hours or until the meat are fork tender.
At this point, I scoop out the meat and transfer them into a plate, then strain out the other ingredients. I cool down the stock and place them (stock and meat) in the fridge, covered, before proceeding with the recipe the following day.
To prepare the other ingredients, first remove the fat from the surface of the beef stock and bring to a gentle simmer. Next, toast the peanuts in a large pan, stirring occasionally until light golden brown. Allow the nuts to cool down and process them in a food processor until finely ground. Transfer to a bowl. Next, grind the raw rice in a spice grinder and toast the in a pan until lightly golden brown. Transfer to a bowl with the ground nuts. Add enough of the hot stock to form a paste and set aside.
To prepare the vegetables, peel and chop the onion, slice the eggplants into 1-inch thick, on a bias, cut the string beans into 2-inch pieces and cut the banana bud half lengthwise, then into 1-inch pieces crosswise. Soak the cut banana heart in water with a little vinegar. Then, juice the calamansi.
To prepare the bagoong, peel and thinly slice the garlic and the shallots. Heat oil in pan over low heat and add the sliced garlic and shallots, and cook until soft. Add the bagoong and cook until the mixture is fragrant. Remove from the heat, transfer to a bowl and set aside.
To cook the Kare Kare, heat oil in a large heavy bottomed pan and sweat the onions, followed by the salt. Cook until the onions are soft. Add 5 cups of the simmering stock and peanut mixture, stirring with a whisk until combined. Then add the beef and let it simmer for 15 minutes until tender. Stir the mixture occasionally. Next, add the eggplant, string beans, banana heart and cook until the vegetables are tender. Add more water if the mixture is too thick. Add the calamansi juice, then season with salt to  taste. Allow to simmer for another 2 minutes and take it off the heat.
To serve the Kare Kare, ladle the dish into a bowl and serve with plain steamed rice and bagoong.