Pat the beef dry and season with salt. Heat the oil in a large Dutch oven over medium-high heat and sear the shanks and oxtail in batches, 3-4 minutes per side, until golden brown.

Return the beef to the pot and add enough water to cover it by 1 inch (about 10-12 cups), scraping up the browned bits. Add 1 onion, the peppercorns and the bay leaf. Bring to a boil (15-20 minutes), skim the foam with a skimmer, then simmer partly covered for about 2 hours, until tender. Reserve 4 cups broth. While the beef simmers, make the rice powder and peanut paste and cut the vegetables.

Toast the glutinous rice in a dry skillet over medium heat for about 10 minutes, until light brown, watching closely since it browns quickly once it starts. Let cool, then grind to a fine powder in a food processor or mortar and pestle. Set aside.

Pulse 1 cup of peanuts in the food processor, setting aside ½ tablespoon crushed peanuts for garnish, then add 2-3 teaspoons avocado oil and a pinch of salt and blend to a paste. Skip if using peanut butter.

In the sauce pot, warm 2 tablespoons avocado oil over low heat. Add the annatto seeds and swirl about 1 minute, until the oil is deep orange, then pour it through a fine-mesh strainer into a heatproof bowl, discard the seeds and return the oil to the pot. Turn the heat to medium, add the chopped onion, garlic and bagoong and cook until the onion is translucent, about 4 minutes.

Add the 4 cups reserved broth and simmer 30 minutes. Meanwhile, heat the oven to 425 degrees Fahrenheit. Whisk in the rice powder and peanut paste and simmer 10-15 minutes, stirring occasionally, until it coats the back of a spoon. Season with 1 tablespoon fish sauce, or to taste. Optional but recommended: blend with an immersion blender, and loosen with a splash of broth if too thick. Add the beef to the sauce and cook 2 minutes, until coated.

While the broth simmers, toss the eggplant with olive oil and salt and roast 30 minutes, flipping halfway, until nicely charred. Meanwhile, boil the green beans 3-4 minutes and the bok choy 2 minutes in salted water. Drain well.

Arrange the beef on a platter, spoon the sauce over, add the vegetables and top with the reserved crushed peanuts and sliced scallions (optional). Serve with rice and bagoong.