This creamy gratin benefits from a subtle blend of spices. Cinnamon, ginger, and cayenne pepper take it from ordinary to out-of-this-world.
Preheat oven to 375 degrees. Pour 1 cup cream into a large ovenproof skillet. Arrange sweet potatoes evenly in pan, season with salt and pepper, and pour remaining cream on top. Gently press on potatoes to submerge. Bring to a simmer over medium, transfer to oven, and bake 12 minutes. Press on potatoes to submerge again and bake until potatoes are tender and cream is bubbling, 8 to 10 minutes more. Sprinkle with cinnamon, ginger, and cayenne. Let cool 10 minutes before serving.