Preheat oven to 375°F.

1. Place sweet potatoes in a saucepan and cover with cold water. Bring to a boil. Reduce heat and simmer for 15 minutes or until tender. Drain and let cool slightly.

2. Place sweet potatoes in a large bowl. Add brown sugar, butter, salt, and vanilla. Mash sweet potatoes with a potato masher.

3. Add 1/4 T. of pecans. Transfer sweet potato mixture to a 11×7-inch baking dish coated with cooking spray. Sprinkle with remaining 1/4 T. of pecans.

4. Top with marshmallows. Bake at 375°F for 25 minutes or until golden brown.