This vegetable will not win a beauty contest but don’t judge a book by its cover. It is part of the celery family. Its stems and leaves are usually used for flavoring cooking liquid or stock and its leaves can be dried and used as a seasoning.
As with beets and carrots, the greens are removed before storing because the greens draw out moisture from the root.
Peel the bulb with a sharp knife then cut down or shred depending on how you will be using the vegetable. The bulb has a mildly sweet, celery-like flavor that is very versatile.
Once scrubbed well the skin even has a use.  The peels can be added to a stock bag in the freezer.  Add to the pot when simmering stock or to the liquid when making rice or other grains.  The skin imparts a mild celery flavor.
Some uses include:
Cube and roast with apples, onions and bacon.
Cube and boil with potatoes – that celery flavor adds a little something-something to mashed potatoes.
Shred along with other veggies and toss the slaw with a vinaigrette.
Cut down along with carrots, potatoes and onions for a beef stew, chicken casserole or veggie pot pie.