Vietnamese
Char the onion and ginger over an open flame until fragrant and blackened.
Blanch the bones briefly, drain, then simmer with the brisket, charred aromatics and toasted spices in fresh water for about 3 hours, skimming often.
Season the broth with fish sauce and rock sugar and strain until clear.
Soak or cook the rice noodles until just tender and divide among bowls.
Top the noodles with cooked sliced brisket and the raw sirloin slices.
Ladle the boiling broth over the raw beef so it cooks in the bowl.
Serve with bean sprouts, Thai basil, lime wedges and sliced chili on the side.