1Remove fat from beef. Cut beef with grain into 2-inch strips; cut strips across grain into 1/8-inch slices.
2Mix broth, garlic, gingerroot, soy sauce, brown sugar and five-spice powder in medium glass or plastic bowl. Mix cornstarch and cold water; stir into broth mixture. Stir in beef until evenly coated. Let stand 10 minutes. Drain beef; reserve marinade.
3Spray nonstick wok or 12-inch skillet with cooking spray; heat over medium-high heat. Add beef; stir-fry 2 minutes. Stir in bell peppers and onions and reserved marinade; reduce heat to medium.
4Cover and cook 3 to 5 minutes, stirring occasionally, until sauce is thickened. Serve over rice.