I found this recipe from Better Homes and Gardens November 2009 issue.
Prep: 45 minutes Bake: 36 minutes Oven: 350 degrees
4 1/2 lbs. sweet potatoes
2 tbsp. olive oil
1 tbsp. salt
1/2 cup butter
2/3 cup whipping cream or half and half
2 tbsp. maple syrup (sugar free please)
1/4 tsp. nutmeg
1 tsp. salt
2 cups mini marshmallows (optional)
1/4 – 1/2 cup pecan halves, toasted
1. Pre-heat oven to 350. Scrub potatoes and prick with a fork. Brush with olive oil. Sprinkle salt over potatoes. Place potatoes in 15x10x1-inch baking pan. Roast, uncovered, 30 to 40 minutes or until soft. Cool until easy to handle.
2. Increase oven temperature to 450 degrees. Halve potatoes, scoop out flesh and discard skin. Mash and transfer to a large bowl.
4. Sprinkle marshmallows on potatoes, bake uncovered, 12 to 15 minutes or until marshmallows are golden brown. Sprinkle pecans. Serve.