Lemon Thai Beef

This recipe I found in the newspaper one day. We make this all the time. Great stir fry dish.
Ingredients:
1 large flank steak
1/3 cup soy sauce
1/4 cup lemon juice
1/4 cup water
2-3 tsp. red pepper flakes
4 garlic cloves
1 tbsp vegetable oil
4 green onions, cut into 2" pieces
4 carrots, thinly cut into strips
2 tsp cornstarch
Ramen noodles or white rice
large ziplock bag
Directions:

1. Cut steak into strips and place in large ziplock baggies
2. make marinade (soy sauce and next 4 ingredients) Pour in baggie over steak.
3. cover and chill marinate for 30 minutes. drain steak.
4. stir fry the steak on medium heat. remove from skillet.
5. stir fry veggies for 3 minutes.
6. whisk cornstarch into remaining marinade. add it to veggies in pan. 
7. add steak back into pan. let sit for 5-10 minutes to setup sauce. 
8. serve over rice or noodles