Roast the bones and aromatics

• Spread the beef bones on a baking tray and roast until deeply charred and golden.
• Add the onion and ginger and roast until charred and smoky.

Simmer the broth

• Transfer the roasted bones, onion and ginger to a stockpot and cover with the water.
• Bring to a simmer and cook for a few hours so the flavor and color transfer to the broth.

Cook the beef

• Add the beef chuck to the simmering broth and cook for two hours.
• Remove the beef and immediately soak it in an ice bath to stop it from overcooking.

Toast and add the spices

• Toast the star anise, cinnamon stick, cloves and coriander seeds until fragrant.
• Tie the toasted spices in a bag and add them to the broth about one hour before serving.

Season the broth

• Season the broth with the fish sauce for a deep umami flavor.
• Add the rock sugar and salt to balance the broth.
• Remove the spice bag after about 30 minutes so it doesn't overpower the broth.

Strain and serve

• Strain the broth through a sieve to make it super clear.
• Slice the chilled beef and serve the broth over rice noodles with the beef.