1. Combine brown sugar, sherry, soy sauce, ginger, garlic, and five-spice powder in shallow 1-1/2-quart microwave-proof dish. Add chicken and turn to coat. Cover and microwave on 100 percent power (High) 10 minutes, turning chicken halfway through. Transfer chicken to platter.
2. Dissolve cornstarch in cold water and stir into pan juices. Microwave, uncovered, on 100 percent power (High) 1-1/2 minutes more. Stir and pour over chicken. Garnish with green onions, if desired. Serve with wild and white rice and steamed watercress, if desired. Makes 4 servings.