Par-boil beef bones in a large pot of boiling water for about 10 minutes, then rinse under cold water. Return bones to the pot, cover with water, add salt and ginger, bring to a boil, and then simmer for 6-8 hours.

With 3 hours left on the broth, tie brisket and beef shank with kitchen twine, par-boil for a couple of minutes, then rinse. Add brisket first, simmer for 2.5 to 3 hours, then add shank to cook until tender for 1 to 1.5 hours.

About 2.5 hours before serving, char onions, ginger, and shallots in a grill pan or oven at 450°F until soft and bubbling.

Toast spices in a dry skillet over medium heat for 3-5 minutes, then add to the broth along with the charred aromatics, and simmer for an additional 2 hours.

Taste the broth after simmering; adjust seasoning with salt, fish sauce, and rock sugar.

Prepare serving bowls with sliced brisket and shank over rice noodles, ladle the hot broth over, and garnish with onions, scallions, and cilantro.