Skim off all but 2 tablespoons fat from drippings in roasting pan. Stir in broth or water. Cook over medium heat, stirring to loosen brown bits. Remove from heat.
Stir corn starch and 1/4 cup cold water in a small bowl until smooth; stir into roasting pan. Bring to a boil while stirring constantly over medium heat and boil 1 minute.
Microwave Directions: Combine all ingredients in a 2-quart, microwave-safe bowl. With a whisk, stir until corn starch is completely dissolved. Microwave on HIGH (100%) power for 7 to 9 minutes or until mixture boils, stirring every minute. Boil for 1 minute. Season with salt and pepper.