Celeriac or Celery root is not just the root of the celery we buy in stores. Celeriac is a variety of celery (turnip-rooted celery, or knob celery) that is grown specifically for its underground tuber. It has a mild celery taste, and is crisp and fresh. It is an excellent source of Vitamins B6, K and C and several minerals (phosphorous, manganese, molybdenum and potassium). Unlike a lot of other tuberous vegetables, celeriac only has about 5-6% starch (versus ~22% in potatoes). Celeriac is quite commonly used in French cooking.
Cleaning & Prepping Celeriac: We've all heard "beauty is only skin deep" ... well in this case, Ugliness is only skin deep!! There are several videos on youtube.com showing how to clean Celeriac. I used a combination of several. I first rinsed the outside really well under running water to get rid of as much dirt as possible. Cut both ends to make flat bases so that you can hold it flat while shaving off the thin skin. I used a chef's knife to do the coarse shaving and then used a small paring knife to get the little bits/eyes that were left behind. Then, I washed it again, under running water, and then cut it into large chunks for this recipe. It is slightly tougher than an apple, but not as tough as some of the squashes out there.