Preheat oven 350

Place sweet potatoes in large saucepan with enough water to cover. Bring to a boil and cook until tender. (About 15 mins). Remove from heat. Drain, mash.

Place mashed sweet potatoes in large bowl and use an electric mixer to blend w/ margarine, brown sugar, orange juice, and cinnamon.

Spread evenly into a 13X9 pan. Top with marshmallows.

Bake at 350 for 25-30 mins or until heated through and marshmallows are puffed and golden brown.