Preparation for most uses is simple. Trim off the top and any straggly root at the bottom and use a peeler to remove the skin. For roasting or cooking to purée, cut the root into convenient lengths and then halve or quarter the pieces lengthwise. Watch out for and remove any woody cores.
To make a purée, peel and dice equal quantities of parsnips and potatoes. Cook each vegetable separately in simmering, salted water until tender. Purée then together and season with salt, pepper and butter. Add warm milk until the desired consistency. I find the flavor improves if the purée is held in a double boiler set up over simmering water for 10 minutes.
You can make a delicious combination of roasted vegetables combining parsnips with turnips, rutabaga, celery root, fennel bulbs—in any proportions, according to your preference. Add a good amount of butternut squash, too.
Trim and peel the vegetables and cut into about ½-inch slices. Fennel should be trimmed and cut into ½-inch wedges. Toss the vegetables in enough melted butter or olive oil to coat all lightly and season with salt and pepper.
Spread out on a large baking sheet with low sides and roast 30 to 40 minutes in a preheated oven at 400°F. Stir them from time to time with a broad spatula so they don’t stick or burn. They are done when tender and lightly caramelized. Over roasting can make them bitter.
Check the seasoning before serving and sprinkle with your choice of chopped fresh herbs such as sage, thyme or winter savory.
Peel and slice the parsnips a little less than 1/8-inch-thick. Heat cooking oil to 365°F. and fry the chips as you would potatoes, until golden brown. Drain on paper towels and salt lightly. Serve while still hot, or keep warm in a low oven if doing several batches.
You can also “oven fry” the slices by tossing them with oil or butter and spreading on a baking sheet. Place in a preheated oven at 475°F. for 5 minutes. Remove and turn with a spatula and bake for another 5 minutes, or until nicely browned.