Prepare the Sauce: In a small bowl, whisk together soy sauce, hoisin sauce, oyster sauce, and sesame oil. Set aside.

Cook the Noodles: Bring a large pot of water to a boil. Cook the lo mein noodles according to package instructions until al dente. Drain and set aside.

Cook the Beef: Heat 1 tablespoon of vegetable oil in a large skillet or wok over medium-high heat. Add the sliced flank steak and cook for about 2-3 minutes until browned. Remove the beef from the skillet and set aside.

Sauté the Aromatics: In the same skillet, add the remaining 1 tablespoon of vegetable oil. Add the minced garlic and the white parts of the scallions. Sauté for about 30 seconds until fragrant.

Add the Vegetables: Add the broccoli florets, sugar snap peas, and shredded carrots to the skillet. Stir-fry for 3-4 minutes until the vegetables are tender-crisp.

Combine Everything: Return the cooked beef to the skillet with the vegetables. Add the cooked noodles and pour the prepared sauce over the top. Toss everything together to ensure the noodles and ingredients are evenly coated with the sauce. Cook for an additional 2 minutes until everything is heated through.

Serve: Garnish with the green parts of the scallions. Serve hot and enjoy your homemade Beef Lo Mein!