Peel and cube sweet potatoes and place in baking dish. Top evenly with 6 pats of butter and sprinkle with salt. You can add cinnamon if you prefer. Bake uncovered for 1 hr or until sweet potatoes are soft.
Sprinkle the top with marshmallows and return dish to oven and broil on LOW until golden. Sprinkle with chopped toasted pecans if desired and enjoy!