COMBINE corn starch and cider in a small bowl until smooth. Set aside. COOK stock over medium heat until hot. STIR corn starch mixture into the stock using a wire whisk. Add the sage. Stirring constantly, bring to a boil. Boil 1 minute, until thickened. If desired, season with salt and pepper to taste. Microwave directions: Combine all ingredients in a 2-quart, microwave-safe bowl. With a whisk, stir mixture until corn starch is completely dissolved. Microwave on HIGH (100%) for 7 to 9 minutes or until mixture boils, stirring every minute. Boil for 1 minute. Season with salt and pepper.