Char the onion and ginger over an open flame or under a broiler until blackened and fragrant.
In a large pot, toast the star anise and cinnamon stick for 1-2 minutes until aromatic.
Add the beef bone broth, charred onion, ginger, and fish sauce to the pot and simmer for at least 20 minutes.
While the broth simmers, cook the rice noodles according to package instructions, then drain and set aside.
Strain the broth to remove the solids and return the clear liquid to the pot, seasoning with sea salt and black pepper.
Place the cooked noodles in a large bowl and top with the raw, thinly sliced beef.
Pour the boiling hot broth over the beef to cook it instantly until tender.
Garnish with bean sprouts, cilantro, Thai basil, sliced scallions, jalapeño, and a squeeze of fresh lime.