Parsnips are a winter root vegetable that is much too much neglected these days. (For that matter, all the winter root vegetables get neglected since people have been able to eat frozen green beans and corn year round. It's a pity. Eating no more different veggies than you can count on the fingers of one hand gets boring, boring, boring.)
.
Dutch soup veggies always include parsnips and leeks along with the onions, celery, and carrots (plus potatoes, cabbage, and tomatoes for groentesoepe, Dutch vegetable soup). Try using those in your next split pea soup along with just a little curry powder (a common Dutch variation since they colonized the East Indies).
I consider them an essential addition to any New England/Irish corned beef or mutton boiled dinner.
They roast up sweet. Toss in oil and salt, roast in the oven, and top with some bacon bits. Or add an assertive green herb like rosemary or thyme when roasting.
They mash like potatoes, good done with butter and roast garlic. Or try a mashed potato, rutabaga, and parsnip combo.
As in the previously posted recipe under turnips, those two make a great pair in a gratin casserole. Parsnips and carrots are another good combo (one that improves my mother's zesty roast carrots with mayo, mustard, and horseradish).
I find they work well in almost any cauliflower recipe.
Here is a whole set of illustrative parsnip recipes:
19 Awesome Parsnip Recipes for Mains, Sides, and More