Preheat the Instant Pot on Sauté setting. When the inner pot is hot, pour in 2 tbsp of oil. When the oil is shimmering, add the garlic and onion and sweat until aromatic and soft, about 2 to 3 minutes
Add salt, pepper, water, and oxtail to the inner pot. Select Meat/Stew setting on High Pressure for 45 minutes.
When cooking time on the Instant Pot is complete, release the pressure. Unlock and carefully remove the lid and remove excess oil using a spoon.
Add peanut butter and fish sauce and mix well. Finally, add the annatto powder and mix until uniform color.
Add the string beans, bok choy and eggplant. Select Sauté setting and cover. Cook vegetables to your desired softness, at least 3 minutes
Serve over rice with a side of bagoong.
