1. Preheat oven to 400°. Bake sweet potatoes 1 hour and 15 minutes or until tender. Let cool 10 minutes, and peel. Reduce oven temperature to 350°.
2. Mash potatoes with a potato masher or fork until smooth, or press through a ricer. Stir in crushed pineapple and next 4 ingredients. Spoon mixture into a lightly greased 13- x 9-inch baking dish.
3. Bake at 350° for 20 minutes. Sprinkle marshmallows and coconut over top, and bake 8 to 10 more minutes or until golden.