Rutabaga, Sweet Potato, and Orange Casserole

Thought to be a cross between a cabbage and a globe turnip, the smooth, heavy, pale yellow rutabaga has been a popular root vegetable in the South since it migrated from Europe with the early settlers in the seventeenth century. Small, relatively tender, and slightly sweet rutabagas can be boiled and mashed or simply cut into strips and blanched for salads, but since the more common large ones tend to be pithy and bitter, most Southern cooks prefer to bake them slowly with sweet potatoes, c