1. Roast the beef bones, onion, and ginger in the oven at 400°F for 30 minutes.
2. Transfer to a large pot, add water, and bring to a boil. Skim off any foam.
3. Add star anise, cinnamon, coriander seeds, salt, sugar, and fish sauce. Simmer for 3 hours.
4. Strain the broth and return to the pot. Keep warm.
5. Cook rice noodles according to package instructions. Drain and set aside.
6. To serve, place noodles in bowls, top with raw beef slices, and ladle hot broth over. Add bean sprouts, lime wedges, fresh herbs, and chili peppers.