- 1 tablespoon soy sauce
- 1 teaspoon cornstarch
- 1/3 cup cold water
- 1 1/2 pounds beef loin sirloin steak, cut crosswise into 3- by 1/4- by 1/4-inch strips
- 1/2 teaspoon salt
- 1/4 teaspoon black pepper
- 1/4 cup olive oil or vegetable oil
- 4 bell peppers in assorted colors, cut into 1/4-inch-thick strips
- 1 large onion, halved lengthwise and cut crosswise into 1/4-inch-thick slices
- 3 cloves garlic, sliced
- 2 tablespoons cold water
- Stir together soy sauce, cornstarch, and 1/3 cup water in a cup.
- Pat steak dry and sprinkle with salt and pepper. Heat 2 tablespoons oil in a 12-inch heavy skillet over moderately high heat until hot but not smoking. Stir-fry half of steak until browned but still pink inside, about 4 minutes. Transfer to a bowl with a slotted spoon and repeat with remaining steak, adding 1 tablespoon oil to skillet.
- Add remaining tablespoon oil to skillet and stir-fry bell peppers, onion, and garlic, until onion is golden, 6 to 7 minutes. Stir in remaining 2 tablespoons water and cook, covered, 3 minutes. Return steak to skillet, then stir in cornstarch mixture. Bring to a boil and cook, stirring, 2 minutes.