Makes: 6 servings. Prep: 15 minutes. Cook: 13 minutes.
In a medium-size bowl, whisk together broth, soy sauce, vinegar, cornstarch and Szechwan seasoning. Set aside.
In a large nonstick skillet or wok, heat oil over high heat. Season sliced flank steak with salt and stir-fry 3 minutes. Remove beef to a plate and keep warm.
Add beans, mushrooms and onion and stir-fry over high heat for about 8 minutes or until beans are crisp-tender. During the last 2 minutes, add 1/4 cup water and cover.
Whisk sauce again and stir in. Add meat back to skillet and stir until all ingredients are combined. Cook for 2 minutes until thickened.
Sprinkle toasted walnuts on top; serve with cooked brown rice.
