How to Make It
Stir the stock, cornstarch, soy and garlic powder in a small bowl until smooth.
Stir-fry the beef in a 10-inch nonstick skillet over medium-high heat until it's well browned. Add the peppers to the skillet and stir-fry until tender-crisp.
Reduce the heat to medium. Add the stock mixture to the skillet. Cook and stir until the mixture boils and thickens, stirring constantly. Serve over the rice.