Cook noodles according to package instructions. Drain and set aside.
In a large skillet or wok, heat sesame oil over medium heat. Add garlic and ginger, sauté for 30 seconds until fragrant.
Add ground beef and cook for 6–7 minutes, breaking it up, until fully browned. Drain any excess fat.
In a small bowl, whisk together soy sauce, brown sugar, and beef broth. Pour into skillet with beef and stir to combine.
Bring to a simmer, then add the cornstarch slurry. Stir until sauce thickens, about 2 minutes.
Add cooked noodles and toss until fully coated in the sauce. Stir in red pepper flakes if using.
Serve hot, garnished with chopped green onions and optional veggies.
