Celeriac is the root bulb of the celery plant. As you might imagine, it has a bit of celery flavor, but not as strong as the greens stalks.
It has a lot of nutrients and has a lower glycemic index (less carbs) than other root vegetables.
Think of it as a weird-looking, but tasty, healthy potato.
For sure you don't have to deep fry celeriac or any other veggies. You could boil and mash or roast or shred and top on anything or make into a soup.
But, I mean... why not try deep-fried?
They are like healthy deep-fried potatoes, what's not to love?
Your oil should get strained and reused... lots of times. Make donuts or fried chicken or... yeah, don't waste it!