This is another family favorite, especially around the holidays. We typically double this recipe for large family functions.
Mash sweet potatoes in a large bowl until smooth.
Add sugar, vanilla, melted butter, cinnamon, egg and pecans and mix well.
Arrange pineapple rings in a baking dish and cover rings with mounds of sweet potato mixture.
Bake 20-25 minutes in 350 degree oven.
Remove from oven and cover sweet potatoes with marshmallows and bake another 5 minutes.