Closely related to carrots and parsley, parsnips have long, tuberous, cream colored roots and are sweeter in taste than other plants in the family. Native to Eurasia, the parsnip has been used as a vegetable since antiquity, when it was cultivated by the Romans (There apparently is some confusion among scholars about this since Romans, including Pliny the Elder in the first century AD, sometimes called both parsnips and carrots pastinaca, and carrots, in Roman times, were either purple or white).
In medieval Europe, parsnips served as a sweetener in a period when sugar was a rare, imported luxury and honey was expensive. They also provided starch before the potato arrived from the New World. Parsnips now are mainly eaten in northern Europe, to a lesser degree in Britain, and hardly at all in southern Europe. But roasted parsnips are considered an essential part of Christmas dinner in some parts of the English speaking world and frequently accompany a Sunday roast. They also often are included in soups and stews.
Parsnips arrived in North America with French colonists in Canada and with the British in the Thirteen Colonies. Originally used as a starchy vegetable, parsnips were replaced by potatoes in the mid nineteenth century and, as was the case in Europe, thereafter were less widely cultivated. It is possible that parsnips are popular in colder climates because they are one of the few vegetables that are improved by frost; freezing the living root causes it to convert some of its starch into sugar. Thus, the plant is commonly left in the ground until it is needed.
The tuber can be baked, boiled, fried as chips, mashed or steamed. Some recipes advise against peeling parsnips on the grounds that peeling reduces the flavor of the vegetable, but peeling is recommended in others. And most recipes suggest removing the woody core when parsnips are trimmed.