Although Weight Watcher friendly at 7 points, this wonderful stir fry is by no means lacking in flavor. The sauce can be made up 3 days in advance...freeze for up to 2 months. Stir fry just before serving
Sauce: In a bowl, mix sauce ingredients together until smooth, Set aside.
Preheat grill: grill beef on high until medium rare, about 5 - 8 minutes. Slice steak thinly and keep covered.
Stir Fry: In a large wok, heat oil over medium heat; stir fry onions for about 5 minutes or until softened. Add peppers; stir fry for 3 minutes. Add sauce to veggies and stir fry for 2 minutes or until sauce thickens, Add beef , mango, cilantro and onions at the end just to coat.