
This Taiwanese beef noodle soup is rich, deeply savory, and packed with tender beef, aromatic spices, and springy wheat noodles. Make it in the Instant Pot for convenience or simmer it on the stove for a classic slow-cooked finish.
Bring a large pot of water to a boil. Add the beef shank, return to a boil, and cook for 1 minute to remove impurities. Drain, rinse the beef well under fresh water, and set aside.
If making your own spice bundle, place the Chinese cinnamon stick, bay leaves, fennel seeds, cumin seeds, coriander seeds, Sichuan peppercorns, and black pepper in a spice bag or a piece of cheesecloth tied securely.
Set the Instant Pot to Saute. Add the oil, then cook the ginger, garlic, scallions, and onion for 3 to 5 minutes, stirring often, until fragrant and the onion begins to soften. Add the tomato and dried chilies, and cook for 1 to 2 minutes more.
Add the blanched beef to the pot. Stir in the tomato paste, spicy bean paste, sugar, soy sauce, and Shaoxing wine. Mix well so the beef is evenly coated.
Pour in the water and add the spice bundle. Lock the lid and set the valve to sealing. Pressure cook on high using the Meat/Stew setting for 100 minutes. Let the pressure release naturally for 15 minutes, then carefully vent any remaining pressure. For the stovetop method, transfer everything to a large pot, cover, and simmer gently for 3 to 4 hours, until the beef is very tender.
When the broth is ready, remove the spice bundle. Taste and adjust seasoning if needed. Cook the wheat noodles according to the package directions. During the last 1 to 2 minutes of cooking, blanch the bok choy in the same pot until just tender.
Divide the noodles among serving bowls and ladle the hot broth and beef over the top. Add bok choy, then finish with cilantro, extra scallions, and pickled mustard greens. Serve immediately while hot.
For the best texture, slice or chunk the beef only after it becomes tender. If you do not have a homemade spice bundle, use a store-bought Chinese aromatic herb packet instead. The soup tastes even better the next day, and the broth can be refrigerated for up to 4 days or frozen for up to 2 months.
