Place the sweet potatoes into a pot of cold water with salt and bring to a rapid boil; about 20 minutes. Drain and return back into pot to mash.
In a medium saucepan, combine the remaining ingredients, except the brown sugar. Allow to simmer over medium heat until butter is melted and mixture is creamy. Pour mixture over potatoes, adding a dash of salt for flavor and stir. Sprinkle potatoes with brown sugar.