Gather beef bones, beef chuck or brisket, onion, ginger, star anise, cinnamon stick, cloves, coriander seeds, fennel seeds, fish sauce, salt, sugar, rice noodles, and toppings like bean sprouts, Thai basil, lime, jalapeños, and hoisin or sriracha
Roast the beef bones, onion, and ginger at 450°F until browned
Rinse the bones well under cold water
Add the bones to a large pot and cover with cold water
Bring to a boil for a few minutes, then drain and rinse the bones again
Return the cleaned bones to the pot and add fresh water
Add the roasted onion and ginger
Toast the star anise, cinnamon, cloves, coriander seeds, and fennel seeds, then add them to the pot
Simmer gently for several hours, skimming off foam and fat as needed
Add fish sauce, salt, and a little sugar to taste
Strain the broth and keep it hot
Cook the rice noodles according to package directions
Slice the beef thinly
Place cooked noodles in bowls
Add raw thin-sliced beef or cooked beef on top
Ladle the hot broth over the noodles and beef
Top with bean sprouts, Thai basil, lime, jalapeños, and sauces as desired
Serve immediately