Char the ginger and onion halves under a broiler for 5 minutes until blackened slightly, then set aside.

Toast the star anise, cinnamon stick, and cloves in a large dry pot over medium heat for 2 minutes until fragrant.

Pour the beef broth into the pot with the toasted spices, charred ginger, and onion. Bring to a boil, then reduce heat and simmer for 30 minutes.

Stir the fish sauce into the broth, then strain the liquid through a fine-mesh sieve, discarding the solid spices and aromatics. Return the clear broth to the stove and keep it at a rolling boil.

Cook the rice noodles according to the package directions, then drain and divide evenly among serving bowls.

Top the warm noodles with the raw, thinly sliced sirloin.

Ladle the boiling hot broth directly over the raw meat to cook it instantly in the bowl.

Garnish with green onions and serve immediately with bean sprouts, cilantro, mint, chili peppers, and lime wedges on the side.