Prepare the noodles according to the package directions.
Cut flank steak into thin strips, about 2 x 1/4 inch..
In a medium bowl, mix 1 tablespoon of cornstarch and 1 tablespoon of soy sauce.
Toss the beef strips in the soy sauce mixture and marinate for 10 minutes to tenderize.
In a medium bowl, mix 2 tablespoons soy sauce, hoisin sauce, sugar and ginger. Reserve.
Place a large skillet or wok over medium-high heat and add vegetable oil.
When the oil is hot, add the beef strips and stir fry for 2-3 minutes until the beef is no longer pink.
Add the minced garlic, sliced carrots and broccoli. Stir fry for 5 minutes or until vegetables are tender.
Add lo mein to the beef and vegetable mixture and toss with the reserved lo mein sauce and sesame oil.
Garnish with sesame seeds and serve immediately.