4 pounds sweet potatoes (about 5 large), peeled and cubed
1 cup 2% milk
1/2 cup packed brown sugar
6 tablespoons butter, softened
1 egg, lightly beaten
1-1/2 teaspoons ground cinnamon
1-1/2 teaspoons vanilla extract
3/4 teaspoon ground allspice
1/2 teaspoon salt
1/4 teaspoon ground nutmeg
18 large marshmallows
Place sweet potatoes in a large saucepan; cover with water. Bring to a boil. Reduce heat; cover and cook for 15-20 minutes or until tender; drain.
Transfer to a large bowl and mash. Add the milk, brown sugar, butter, egg, cinnamon, vanilla, allspice, salt and nutmeg; beat until smooth.
Transfer to a greased shallow 2-1/2-qt. baking dish. Bake, uncovered, at 350° for 40-45 minutes or until heated through. Top with marshmallows. Bake 5-10 minutes longer or just until marshmallows begin to puff and brown.
For a crunchy topping: Omit marshmallows and reduce brown sugar in sweet potato mixture to 1/4 cup. Before baking, combine 3/4 cup all-purpose flour, 3/4 cup packed brown sugar, 3/4 cup chopped pecans and 1/2 cup melted butter in a small bowl. Sprinkle over the mashed sweet potatoes. Bake, uncovered, at 350° for 50-55 minutes or until heated through and topping is browned.