If using fresh sweet potatoes, place in a large saucepan or Dutch oven; cover with water. Bring to a boil. Reduce heat; cover and cook 25-40 minutes or until tender. Drain; cool slightly and peel. Cut into chunks., Preheat oven to 350°. Place sweet potatoes in a 2-qt. baking dish. In a small saucepan, combine butter, syrup, brown sugar and cinnamon; bring to a boil, stirring constantly. Pour over potatoes. , Bake, uncovered, 30-40 minutes or until heated through.