Red-skinned, orange-yellow fleshed sweet potatoes. Their sweet and nutty squash-like flesh, becomes creamy and moist when cooked. Sweet potatoes are great baked whole, sliced into fries, or in a pie. They are also tasty in soups, stews or soufflés. Sweet potatoes keep nicely for up to one month in a cool, well-ventilated, dark place. A cupboard away from excess heat would do. Careful, if left in the refrigerator, their natural sugars will become starch, turning them into not-too-sweet potatoes.