Slice steak thinly across the grain and lightly season with salt and pepper.

Toss shrimp with 1/2 tbsp soy sauce and a pinch of pepper.

Boil noodles according to package directions until just tender; drain and toss with a little oil to prevent sticking.

Whisk together remaining soy sauce, oyster sauce, hoisin, rice vinegar, sesame oil, garlic, ginger, and cornstarch slurry. Set aside.

Heat a large skillet or wok over high heat. Add 1 tbsp vegetable oil. When shimmering, add the steak in an even layer. Sear for 1–2 minutes without moving, then stir-fry for another 30–60 seconds until browned but still slightly pink in the center. Remove steak to a plate and tent loosely with foil to rest.

In the same pan, add the shrimp and stir-fry 1–2 minutes per side until pink and just cooked through. Transfer shrimp to the steak plate.

Add remaining 1 tbsp oil to the pan. Toss in the white parts of the green onions, bell pepper, carrot, and broccoli. Stir-fry 3–4 minutes until vegetables are bright and just tender-crisp. If the pan gets too dry, splash a tablespoon of water to help steam the veggies.

Reduce heat to medium-high. Add the noodles to the pan, then pour the sauce over everything. Toss well to coat the noodles and veg. The cornstarch slurry will thicken the sauce in about 30–60 seconds.

Return steak and shrimp to the pan and toss gently for another minute to combine. Adjust salt or soy if needed, and add red pepper flakes if you like heat.

Remove from heat, finish with the green tops of the onions, and a sprinkle of sesame seeds. Serve immediately.