4 Green Onions, including tender green tops, thinly sliced
How to make it
Trim flank steak of any visible fat. Cut steak lengthwise, with the grain, into strips about 2-inches wide. Cut the strips of meat on the diagonal, across the grain, into pieces 2-inches wide and about 1/4-inch thick. Place in a large bowl, and sprinkle with 2 tsp. of the cornstarch; stir and toss until the meat is coated. Set aside.
In a cup, combine the remaining 1 tsp. cornstarch with the soy sauce, sherry and 1/4 cup of the water; stir until blended, then set aside.
Cut zucchini and crookneck squashes into rounds 1/4-inch thick.
Thinly slice the yellow onion.
Place all the ingredients next to the stove.
In a nonstick wok or large, deep nonstick frying pan over high heat, warm 2 tsp. of the oil. When hot but not smoking, add the squashes and yellow onion; toss and stir almost constantly for 3 minutes. Add remaining 1/4 cup water, cover and cook for 2 minutes. The vegetables should be tender crisp but not crunchy. Transfer to a shallow dish; set aside.
Wipe out the pan with paper towels and return to high heat.
Add the remaining 2 tsp. oil to the pan. When hot, add the meat and toss and stir constantly for 2 minutes. Return the vegetables and any of their liquid to the pan and stir gently.
Whisk the soy sauce mixture briefly to blend it, then add to the pan along with the green onions. Toss and stir until the meat and vegetables are evenly coated and the sauce has thickened slightly, about 1 minute. Serve at once.