Cook noodles according to package instructions, drain, and set aside.

In a small bowl, whisk together soy sauce, brown sugar, beef broth, and cornstarch until smooth.

Heat vegetable oil in a large skillet or wok over medium-high heat.

Add ground beef and cook until browned, breaking it into small crumbles; drain excess fat.

Stir in minced garlic, ginger, and red pepper flakes; cook for 60 seconds until fragrant.

Pour the sauce mixture over the beef and simmer for 2-3 minutes until the sauce thickens and coats the meat.

Add the cooked noodles to the skillet and toss thoroughly to combine.

Remove from heat, drizzle with sesame oil, and garnish with sliced green onions before serving.