1. Bring a large pot of salted water to a boil and cook the egg noodles according to package instructions, usually about 6-8 minutes until al dente. Drain and set aside.
2. While the noodles cook, prepare the teriyaki sauce by whisking together soy sauce, mirin, brown sugar, and sesame oil in a small bowl. Set this aside to let the flavors meld.
3. Heat 1 tablespoon of vegetable oil in a large skillet or wok over medium-high heat. Once hot, add the sliced steak in a single layer. Let it sear undisturbed for about 2 minutes to get a nice crust, then stir-fry for another 2-3 minutes until cooked through but still tender. Remove the beef from the pan and set aside.
4. In the same skillet, add the remaining tablespoon of oil. Toss in the minced garlic and grated ginger. Sauté for about 30 seconds until fragrant but not browned.
5. Add any optional vegetables like shredded carrots or snap peas now, and stir-fry for 2-3 minutes until just tender-crisp.
6. Return the cooked beef to the pan along with the noodles. Pour the teriyaki sauce over everything and toss well to coat. Cook for another 1-2 minutes, allowing the sauce to thicken slightly and cling to the noodles and beef.
7. Remove from heat and stir in the sliced green onions. Sprinkle with toasted sesame seeds before serving.

One tip I’ve learned over years of cooking is to slice the beef thinly and against the grain—it makes all the difference in tenderness. Also, don’t rush the searing step; that caramelized crust adds so much flavor that your family will savor in every bite.