Sprinkle lemon juice over pears. Melt sugar and butter in a large nonstick skillet over medium heat, stirring occasionally, 2 minutes or until melted and smooth. Reduce heat to low; add pears, and cook, stirring often, 6 to 8 minutes or until pears are tender.
Whisk together cornstarch and 1 tsp. water. Stir into pear mixture, and cook 1 minute or until thickened.