Beef stir-fry is a quick and easy dish that is perfect for busy weeknights. Thinly sliced beef is cooked with a variety of colorful vegetables like bell peppers, broccoli, and carrots in a flavorful sauce. The key to a successful stir-fry is high heat and quick cooking to retain the crispness of the vegetables and the tenderness of the beef. Serve it over steamed rice or noodles for a satisfying and nutritious meal.