How to Make It
Preheat the oven to 350°. In a medium nonreactive bowl, combine 3 cups of water and the sherry, orange juice, soy sauce, honey, cinnamon, five-spice powder, garlic, ginger, coriander seeds and crushed red pepper.
In a large enameled cast-iron casserole, heat the oil over moderately high heat. Season the beef with salt and pepper. Add the beef to the casserole and cook until browned, about 5 minutes per side. Drain any fat.
Add the onion and the sherry mixture to the meat, cover and bring to a boil. Cook the meat in the oven for about 2 1/2 hours, or until very tender; turn the meat halfway through cooking.
Meanwhile, in a large bowl, cover the rice noodles with cold water and let soften, 20 to 30 minutes. Drain and set aside.
Transfer the beef to a large platter, cover with foil and keep warm. Skim the fat from the broth and add the bok choy and red bell pepper, if using. Simmer over moderate heat until the bok choy is just tender, 3 to 5 minutes. Season with salt and pepper. Add the noodles and simmer just to heat through.
To serve, cut the beef across the grain into 1/2-inch-thick slices. Transfer the noodles to 6 warm shallow bowls and top with slices of beef, red bell pepper and bok choy. Ladle the broth over all and garnish with the cilantro and mint.