Place sweet potatoes in a large saucepan or Dutch oven; cover with water. Bring to a boil. Reduce heat; cover and cook for 25-30 minutes or until tender. Drain., In a large bowl, beat the sweet potatoes, milk, egg substitute, brown sugar, salt and vanilla until smooth. Transfer to a 1-1/2-qt. baking dish coated with cooking spray. Sprinkle with cinnamon. Bake, uncovered, at 350° for 25-30 minutes or until heated through.