Position knife blade in food processor bowl; add orange. Pulse 8 times or until orange is finely chopped. Spoon orange into a 2-quart glass measure. Add sugar and lemon juice; stir well. Microwave at HIGH 17 to 21 minutes or until thickened, stirring every 3 minutes. (Mixture will continue to thicken as it cools.) Let cool. Store in an airtight container in refrigerator up to 1 week.