• Gather all the ingredients. If you‘re making the homemade yakisoba sauce, gather the additional condiments (see the image on the right).
  

To Make the Homemade Yakisoba Sauce

• In a mason jar, combine 2 Tbsp oyster sauce, 2 Tbsp ketchup, 1½ Tbsp soy sauce, and 1½ Tbsp sugar for the sauce (don‘t add the Worcestershire sauce yet). Mix well together. Make sure that each ingredient is well incorporated.
  
• Add 7 Tbsp Worcestershire sauce and whisk it all together. Set aside.
  

To Prepare the Ingredients

• Thinly slice ½ onion and ¼ green bell pepper. If the bell pepper is tall, cut the slices in half crosswise.
  
• Discard the tough core of 6 oz green cabbage leaves. Cut the leaves into pieces 1 inch (2.5 cm) square.
  
• Cut 2 oz carrot into 2-inch (5-cm) lengths and slice into thin slabs. Then, cut them into julienned strips.
  
• Cut 3 green onions/scallions into 2-inch (5-cm) lengths and cut the thick bottom parts in half lengthwise.
  
• Cut off and discard the stems of 6 shiitake mushrooms and thinly slice the caps.
  
• Slice ½ deep-fried firm tofu cutlet (atsuage) and cut the slices in half lengthwise to make thin strips.
  

To Cook the Yakisoba

• Heat a wok (or large frying pan) on medium-high heat. Once it’s hot, add 1 Tbsp neutral oil and swirl it around to make sure it coats the entire surface of the wok.
  
• Add the onion and the white part of the green onions. Cook, stirring often, until the onion slices are translucent.
  
• Add the bell pepper, cabbage, and carrot. Stir to cook until they are mostly wilted.
  
• Add the shiitake mushrooms, green part of the green onions, and tofu. Mix all together.
  
• Add 4 oz bean sprouts and mix everything. I like to keep the texture of the vegetables tender but not too soft, so I move on to the noodles when the vegetables are 80–85% cooked through.
  
• Place the squares of 3 packets yakisoba noodles in the pan on a bed of the stir-fried vegetables. Cover the noodles with the vegetables from the sides of the pan. Then, lower the heat and let the noodles steam for 2–3 minutes.
  
• Increase the heat back to medium or medium high. Gently loosen up the noodles and toss all the ingredients together using a spatula and/or tongs in each hand.
  
• Drizzle 6 Tbsp yakisoba sauce over the ingredients, saving some in case you wish to add more later. Toss everything together and taste; add more sauce if desired.
  

To Serve

• Serve the Vegetable Yakisoba on individual plates and garnish with aonori (dried green laver seaweed) and pickled red ginger (beni shoga or kizami beni shoga).
  

To Store

• You can keep the leftovers in an airtight container and keep them for 3 days in the refrigerator or for up to a month in the freezer.