Parboil the bones

• Place the beef oxtail and beef neck bones in a pot of water.
• Bring to a boil to parboil.

Clean the bones

• Strain the bones and wash them thoroughly.
• Remove all the gunk and gaminess.

Char the aromatics

• Char the yellow onion, cinnamon sticks, star anise and carrots.
• Cut the bottom end portion of the celery stalk.

Start the broth

• Add the water to a large pot and bring to a boil.
• Add the beef oxtail and beef neck bones.
• Add the charred ingredients and the celery stalk.

Season the broth

• Add the rock sugar.
• Add the chicken bouillon, fish sauce, beef paste and five spice seasoning tea bags.

Simmer and top up the broth

• After an hour, top the broth back up to its original level with additional water.
• Repeat with more water for the second hour, then remove the spice bag.
• Keep topping up with water each hour and taste the broth as it develops.
• Fish out and remove the ginger, star anise and cinnamon sticks once they soften.

Finish the simmer

• Add the final water, bring to a boil, then lower the heat to a simmer.
• Cook until the oxtail is fork tender and gelatinous, falling off the bone.

Cook the noodles and serve

• Cook the rice noodles.
• Add the desired proteins and condiments: sriracha, fried garlic, fried onions and chili oil.
• Top with cilantro, scallions and lime, then ladle the broth into each bowl.