Char the onion and ginger over an open flame or under a broiler until slightly blackened and aromatic.
In a large pot, combine the beef bone broth, charred onion, ginger, star anise, and cinnamon stick.
Bring the broth to a boil then reduce heat to low and simmer for 20 minutes to infuse the spices.
While the broth simmers, cook the rice noodles according to package directions, drain, and set aside.
Strain the broth through a fine-mesh sieve to remove the solids and return the clear liquid to the pot.
Stir the fish sauce and black pepper into the hot broth and bring it back to a rolling boil.
Place the cooked noodles in a large bowl and arrange the raw, thinly sliced beef on top.
Pour the boiling broth directly over the beef to cook it instantly and garnish with bean sprouts, basil, cilantro, chili, and lime.