Core pears from bottom end, leaving stems intact. Peel pears. If necessary, cut a thin slice from bottoms of pears to help stand upright.
Place pears in a 2-quart-square baking dish. Stir together lemon juice, vanilla, and cinnamon. Brush onto pears. Pour any extra lemon juice mixture over pears.
Bake, covered, in a 375 degree F. oven for 30 to 35 minutes or until pears are tender. Cool slightly.
To serve, place warm pears, stem end up, on dessert plates. Strain baking liquid; pour liquid into a small bowl. Stir in chocolate-flavored syrup. Drizzle sauce over pears. Serve warm. Makes 4 servings.