Cook noodles according to package directions, drain, and set aside.
Toss steak slices with soy sauce and cornstarch; let sit for *5 minutes*.
Heat olive oil in a skillet over high heat. Sear steak for *2-3 minutes* per side. Remove and set aside.
Reduce heat to medium and add butter. Stir in garlic, brown sugar, red pepper flakes, and beef broth. Simmer for *2 minutes*.
Toss in cooked noodles and steak, mixing well.
Garnish with green onions and serve hot!