Season meat with salt and pepper. Over medium-high heat, sear in a little oil for about 2 minutes on each side. Transfer to a plate.
Reduce to medium heat, then sauté garlic and onion until softened for about a minute.
Add the meat and enough water to cover them, about 6 cups. Let it come to a boil.
Skim off the scum and fat that rise to the surface. Add some salt—I used about 1½ teaspoons of kosher salt (use less for table salt).
Cover and simmer until the meat is tender, about 2 hours.
Blanch yardlong beans in boiling water with a pinch of baking soda for about 2 minutes. Transfer to an ice bath (water+ice).
Blanch bok choy for a minute. Transfer to the ice bath. Drain the vegetables.
In a skillet, fry the eggplant over medium-high heat until browned on both sides. Place them on paper towels to absorb excess oil.
Add annatto, peanut butter, ground peanuts, and sugar when the meat is tender. Mix until the sauce is smooth.
Thicken the sauce with cornstarch or rice flour slurry. Taste and adjust as needed.
Add the vegetables and turn off the heat so they don't overcook.
Serve with a side of sautéed shrimp paste. It is quite salty so add sparingly.