Cook lo mein noodles according to package instructions, then set aside.
Add all beef ingredients except vegetable oil to a bowl, toss, then set aside.
Add all sauce ingredients to a bowl and set aside.
Heat vegetable oil for the beef in a large wok or skillet over high heat, add in the beef and cook for 3-5 minutes or until no longer pink. Transfer to a plate and set aside.
Add vegetable oil for the vegetables to the skillet, then add in the carrots, bell pepper, and mushrooms. Cook for 4 minutes, then add in the cabbage and green onion and cook for an additional 2 minutes.
Transfer beef back to the skillet along with the sauce and noodles, toss everything together until sauce has thickened.
Recipe Notes
Make it Gluten-Free: Use gluten-free soy sauce and either gluten-free spaghetti or zucchini noodles instead of the lo mein noodles.
Make it Vegan/Vegetarian: To make this a vegetable lo mein, use an additional cup of sliced mushrooms instead of flank steak in this recipe.
Recipe yields approximately 4 servings. Nutritional values shown are general guidelines, and reflect information for one serving out of 4. Macros may vary slightly depending on specific types and brands of ingredients used.
To determine the weight of one serving, prepare the recipe as instructed. Weigh the finished recipe, then divide the weight of the finished recipe (not including the weight of the container the food is in) by 4. Result will be the weight of one serving.