To prepare the broth, combine the chicken broth, sliced round steak, cinnamon sticks, cloves, and star anise in a stockpot or a very large saucepan. Bring to a gentle boil over medium-high heat.

Meanwhile, brown the onion and ginger to bring out their flavor: heat a large skillet over medium-high heat until very hot, about 1 minute. Add the quartered onion and ginger and let them cook on one surface until handsomely browned but not burnt. Turn and sear the other surface, and continue cooking until all the pieces are well browned and fragrant. Add the charred onion and ginger to the stockpot, and let everything boil gently for 1 hour.

While the broth is cooking, soften the rice nooidles by immersing them in a medium bowl of warm water until they become flexible and bright white, 15 to 20 minutes. Drain well and set aside.

Remove the broth from the heat, and stir in the fish sauce, sugar, and salt. Strain the broth into a large saucepan, discarding all the solids. Or, if you are preparing your pho in advance, strain the broth into a storage container instead. Let it cool to room temperature, cover, and refrigerate for up to 2 days.

About 30 minutes before you plan to serve the dish, prepare the noodles, boneless beef, and accompaniments. Place the bean sprouts, sliced onion, fresh herbs, green onion, lime juice, and chilies near 4 big Asian-style noodle bowls, pasta plates, or soup bowls in which you will serve the broth. Bring a large saucepan of water to a rolling boil over high heat for the noodles. Meanwhile, pour the broth into a saucepan, bring it to a gentle boil over medium-high heat, and adjust the heat to maintain a lively simmer. Cut the steak in half crosswise, put both pieces in the simmering broth, and cook for 10 minutes, or until medium-rare. Transfer the steak to a cutting board, slice into thin, bite-sized strips, and set aside.

Shortly before serving, cook the noodles: Drop the softened rice noodles into the boiling water, remove from the heat, and let stand for 10 minutes, stirring once or twice to separate any noodle clumps into strands. Meanwhile, bring the simmering broth to a rolling boil.

Drain the noodles well, and quickly divide them up among the 4 bowls (about 1 cup per bowl). Top each noodle bowl with one-fourth of the sliced steak, bean sprouts, onion, herbs, green onion, lime juice, and chilies. Ladle hot broth (about 1½ cups) over the noodles in each bowl, and serve at once. Be sure to provide each guest with a fork or chopsticks, and an Asian soup spoon or a large spoon.