How to Make It
Combine first 5 ingredients. Gradually whisk in 3 Tbsp. oil; transfer to a large zip-top plastic bag. Add steak; seal. Let stand at room temperature 15 minutes. Pour steak and marinade into a bowl. Transfer steak to a wok, reserving marinade. Stir-fry steak in 1 Tbsp. oil over medium-high heat 1 1/2 minutes or until browned. Remove steak. Add beans and bell peppers to wok; stir-fry 3 minutes. Whisk cornstarch into reserved marinade. Stir cornstarch mixture into vegetable mixture. Stir-fry 30 seconds or until sauce thickens. Stir steak into vegetable mixture, and stir-fry 30 seconds. Remove from heat, and serve over rice.