Any trip to Taiwan requires at least one bowl of traditional beef noodle soup; the stew, beef, and often handmade noodles are just a bit spicy, occasionally too salty, and always, always filling enough to fuel another three hours (minimum) wandering through night markets.
*Note: If you like your soup spicier, feel free to add a touch more spicy soybean sauce.
In a large frying pan, heat the cooking oil over high heat until shimmering. Sauté the scallions, ginger, beef, and soybean sauces until the beef is covered in sauce and seared, about 3-4 minutes. Transfer everything to the slow cooker. Add in the soy sauce and mirin.
Pour the hot water into the frying pan to collect the remaining sauce, then transfer to the slow cooker. (You may need more water; make sure the meat is mostly covered.) Stir, then cook on low until the beef is tender, about 6-8 hours.
Bring a large pot of water to boil over high heat. Cook the vegetables until tender, about 2-3 minutes. Remove and set aside. In the same pot, cook the noodles until al dente. Combine everything together with soup, add pepper to taste, and top with the scallions and fresh cilantro.