 In some cases, parsnips are boiled and the solid portions are removed from the soup or stew, leaving behind a more subtle flavor than the whole root, and starch to thicken the dish.Roast parsnip is considered an essential part of Christmas dinner in some parts of the English-speaking world and frequently features in the traditional Sunday roast.Parsnips can also be fried or thinly sliced and made into crisps.