Cube sweet potatoes and combine with enough cold water to cover in saucepan. Bring to a boil; reduce heat. Simmer for 30 minutes or until tender; drain. Mash with a potato masher.
Spoon mashed potatoes into a mixer bowl. Beat until blended. add brown sugar, butter, tangerine juice concentrate, Amaretto, Kahlua, salt, cinnamon and vanilla. Beat until smooth.
Add the eggs, beating until blended. Stir in the pecans. Spoon the sweet potato mixture into a uttered 2-qt. baking dish. Bake at 350 degrees for 20 minutes. Top with marshmallows. Bake until marshmallows are golden brown and are slightly melted.