Slice the flank steak into 1/4 in. strips carefully on a cutting board using a sharp knife. Be sure to cut against the grain.
In a large bowl, toss the Flank Steak with the cornstarch and 1 Tbsp. soy sauce.
1 lb. beef Flank Steak, thinly sliced, 1 Tbsp. soy sauce, 1 Tbsp. cornstarch
Cook the Flank Steak: Heat the vegetable oil in a wok or large frying pan over medium-high heat. Once nice and hot, add in the flank steak strips. Using tongs, flip occasionally to cook on both sides. This won’t take long since the pan is hot and the beef is thin, ~3 minutes. Transfer beef to a plate and set aside.
3 tsp. Vegetable Oil
Steam the broccoli: To the same pan, add in the bite-sized broccoli and turn the heat down to medium. Pour in the water and cover pan with a lid to steam the broccoli. Allow to steam for 3-4 minutes or until broccoli is bright green and tender yet still has a slight crunch.
1 head broccoli, chopped ~1 1/2 cups, 1/2 cup water
Meanwhile, whisk together all of the ingredients for the sauce in a 2 cup measuring cup or small bowl.
1/2 cup beef broth, 2 1/2 Tbsp. dark brown sugar, 2 Tbsp. soy sauce, 2 Tbsp. cornstarch, 3 cloves garlic, crushed, 1 small knob ginger, minced, ~1 tsp., 2 tsp. sesame oil, 1 tsp. unseasoned rice vinegar
Add the cooked beef back into the pan on top of the broccoli. Pour the sauce over the beef and broccoli and lastly add in the scallions. Toss this all together until the sauce thickens and coats the beef and broccoli ~1 minute.
Garnish with more green onions and sesame seeds if desired. Serve with rice or Chow Mein Noodles. Enjoy!
White rice or Chow Mein Noodles, 2 stalks green onions, 1 tsp. sesame seeds (optional)