In a bowl, combine the sliced beef with baking soda and 3 tablespoons of water. Let it marinate for about 15 minutes while you prep other ingredients.
In a large pot, bring water to a boil. Add your chosen noodles and cook according to package instructions until al dente. Drain and set aside, tossing them with a little oil to prevent sticking.
In a small bowl, mix together the soy sauce, hoisin sauce, minced garlic, ginger, and crushed red pepper flakes. Taste and adjust the seasoning if necessary.
In a large skillet or wok, heat the canola oil over medium-high heat. Add the marinated beef and cook for about 3-4 minutes until browned and cooked through. Remove the beef from the pan and set aside.
In the same skillet, add the carrots, broccoli, and red bell pepper. Stir-fry for about 5 minutes until they are tender-crisp. Add the water chestnuts and half of the green onions, stirring to combine.
Return the beef to the skillet with the vegetables. Pour the sauce over the mixture and toss everything together until well coated. Cook for an additional 2-3 minutes to heat through.
Finally, add the cooked noodles to the skillet. Toss everything together until the noodles are evenly coated in the sauce and heated through. Drizzle with sesame oil if using.
Garnish with the remaining green onions and serve hot.
