Bring a large pot of salted water to a boil. Add the noodles and cook until al dente. Drain and set aside.

In a large skillet over medium-high heat, add the ground beef. Use a wooden spoon to break it into small pieces. Cook until no pink remains.

Push the beef to one side of the pan. Add a splash of sesame oil and toss in the minced garlic and grated ginger. Stir for about 30 seconds until fragrant.

In a small bowl, whisk together the soy sauce, chicken broth, brown sugar, and rice vinegar. Pour this mixture over the beef.

Create a small slurry with cornstarch and a tablespoon of water. Stir this into the skillet. Watch as the sauce transforms into a thick, glossy coating.

Add the cooked noodles into the skillet. Use tongs to lift and turn the noodles, ensuring they are completely drenched in the sauce. If using vegetables, fold them in at this time.

Garnish generously with sliced green onions and a sprinkle of chili flakes.