Step 1

Bring a large Dutch oven or stockpot of water to a boil. Add beef bones, oxtail, and brisket. Return to a boil; cook 5 minutes. Drain; return beef bones, oxtail, and brisket to pot.

Step 2

Toast cloves, star anise, cinnamon, peppercorns, coriander, and fennel seeds in a small skillet over medium-high heat, stirring, until fragrant, about 2 minutes. Transfer to pot.

Step 3

Heat broiler. Place onion halves, shallots, and ginger on a rimmed baking sheet. Broil, turning occasionally, until charred in spots, about 10 minutes. Transfer to pot.

Step 4

Add enough water to cover (about 8 quarts). Bring to a simmer over medium-high heat; do not boil. Skim foam with a spoon, adjusting heat as necessary to maintain a simmer.

Step 5

Simmer until broth is golden brown and liquid level has lowered about 2 inches, 6 to 8 hours. Transfer brisket to a dish; let cool, then cover brisket with plastic wrap and refrigerate.

Step 6

Remove bones and oxtail; discard. Strain broth through a sieve lined with cheesecloth. Stir in sugar and fish sauce. Refrigerate overnight or up to 2 days, or freeze up to 1 month.

Step 7

With a large spoon, remove most of hardened fat from surface of broth; discard. Bring broth to a simmer over medium-high heat.

Step 8

Two and a half hours before serving, freeze eye of round until firm, about 2 hours. Slice very thinly against the grain. Slice chilled brisket thinly against the grain as well.

Step 9

At least 30 minutes before serving, place noodles in a large baking dish or bowl. Cover with cool water and let stand until pliable. Drain, rinse, then drain again.

Step 10

Cook noodles in a pot of boiling water until al dente, 3 minutes. Drain; divide among 12 bowls. Top with meats, sliced onions and scallions, and broth. Serve with accompaniments.