1Trim fat from beef. Cut beef lengthwise into 2-inch strips; cut strips crosswise into 1/8-inch slices. Mix 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.
2Drain beef; reserve marinade. Spray nonstick wok or 12-inch skillet with nonstick cooking spray; heat over medium-high heat until cooking spray starts to bubble. Add beef; stir-fry 2 minutes. Stir in bell peppers and onions and reserved marinade; reduce heat to medium. Cover and cook 3 to 5 minutes, stirring frequently, until sauce is thickened. Serve over rice.