- In a large pot, place shank and bones. Cover with cold water and bring to a boil. Simmer for about 10 minutes to remove impurities. Drain and discard broth. Clean the pot.
- Rinse shank and marrowbones under cold water, rubbing to clean them thoroughly. Return to pot. Add onion, garlic, fish sauce, and peppercorns. Cover with water and bring to a boil. Simmer gently, covered, for about 4 hours or until meat falls off the bone. Skim, if needed.
- Reserve meat and marrowbones in a bowl. Trim fat from the meat and remove the bone from the shank. Strain broth through a sieve and return to pot. Season with salt. Add meat, marrowbones, corn, chayote, and Chinese cabbage. Bring to a boil and simmer for about 15 minutes or until vegetables are tender. Add bok choy 1 minute before the end of cooking.
- Place bulalu in the centre of the table. Ladle into bowls. Serve with jasmine rice, vinegar, and sambal oelek. Better eaten with a spoon and a fork.