Place the beef cubes and 4 slices of ginger in a large pot. Cover with cold water by 2 inches. Bring to a boil and cook for 5 minutes, skimming any foam that rises. Drain the beef in a colander and rinse the pieces with water. Discard the cooking liquid and ginger.
While the beef blanches, toast the spices. Place the star anise, cinnamon stick, bay leaves, and coriander seeds in a dry Dutch oven or large pot over medium heat. Toast for 1-2 minutes until fragrant. Remove the spices and set them aside.
Add the neutral oil to the same pot over medium-high heat. Add the onion, tomatoes, garlic, 3 slices of ginger, and scallion whites. Sauté for 3-4 minutes until the onion and tomatoes soften. Stir in the doubanjiang, tomato paste, and brown sugar, and cook for 1 minute.
Return the blanched beef to the pot. Stir to coat the beef with the aromatics. Pour in the Shaoxing wine, soy sauce, and dark soy sauce. Add the toasted spices and 8 cups of water, or enough to cover everything by about 1 inch. Bring the mixture to a boil.
Once boiling, reduce the heat to low, cover the pot, and let it simmer gently for 2 to 2.5 hours. The beef should be very tender when done. The internal temperature will be well above 145°F (63°C).
When the beef is nearly done, cook the noodles according to package directions in a separate large pot of boiling water. In the last 3-4 minutes of cooking, add the bok choy to the pot with the noodles to blanch. Drain both and rinse the noodles briefly to remove excess starch.
Taste the beef broth and adjust seasoning with salt or more soy sauce if needed. Remove the whole spices before serving.
Divide the cooked noodles and bok choy among four large bowls. Ladle the beef and hot broth over the noodles. Garnish with the sliced scallion greens and optional chili oil or pickled mustard greens. Serve immediately.