Roast the beef bones in a preheated oven at 400°F for 30 minutes.
Char the onion and ginger in a pot until fragrant.
Add roasted bones to a large pot with 8 cups of water.
Incorporate star anise, cinnamon stick, and coriander seeds.
Bring to a boil, then reduce to a simmer for 1.5 hours.
Strain the broth and return it to the pot.
Season with salt and sugar to taste.
Prepare rice noodles according to package instructions.
In serving bowls, layer noodles and raw beef slices.
Pour hot broth over the noodles and beef to cook the meat.
Garnish with fresh herbs, bean sprouts, lime, and chili.