Celery root is essentially a type of celery selected for its hearty underground mass as opposed to its fibrous pale green stalks. Unbeknownst to me, celeriac has a long history of cultivation dating back to Homeric times (800 BCE!). It became popular in European cuisine during the 17th century, but remains an oddity in the United States. Still, it serves as a marvelous source of vitamins and fiber ... getting your bang for your buck in this low-calorie veggie.
Despite its unappealing exterior, celeriac is really quite tasty. I usually serve it up with some other roots (beets, turnips, carrot, sweet potatoes, rutabaga, sunchokes, etc.) tossing the lot in olive oil, salt, and thyme. Then roast it in an oven at 400F for an hour.
Others are a bit more creative:
While I'm not familiar with the "remoulade", apparently Inna Garten makes a mean one!
This Celery and Squash Gratin can easily be made vegan with your choice of fat and almond milk!
Celery Root Slaw, for a nice little winter salad.
Fat Free Vegan provides a tasty Celeriac Soup recipe.
Or if you want to be adventurous - Celery Root and Apple Soup might be a better option.
NPR weights in!