Celery Root Soup with Shaved White Truffles

I've been on a tuberous jag lately. It seems that each winter I adopt a different root vegetable for extra attention in the kitchen. Parsnips, beets, turnips, burdock, and yams have all had their due, among others, and let's not forget those tuber-like fungi, truffles. This year the winner is the homely looking celery root. Seems I'm not alone. Celery root, or celeriac, is more prevalent on restaurant menus than ever, usually shaved fresh in salads, roasted with a root medley, or in soup.

Celery root, it's true, is not much for the eyes. It looks a little like some intergalactic critter from the cantina scene in Star Wars, with tentacles and tendrils snaking around. But once you slice off the exterior you're left with a pearly white block of goodness that takes on a pleasing silky character when cooked, not to mention a deep earthy flavor that's reminiscent of a more rough-hewn conventional stalk of celery on steroids. My friend Brad makes cream of chanterelle soup with celery root; the root thickens and softens the soup so much that no actual cream is required.

Celery root marries nicely with other roots and gourds. You'll often see it paired in soup with parsnip or butternut squash. Recently I combined it with leftover roasted acorn squash along with yellow curry powder, fresh ginger, and garam masala, then served it with sour cream and cilantro. My favorite way to use celery root is solo. A celery root soup is about the easiest soup you can make and the payoff is well beyond the ease of preparation. The flavor is jaunty and rich enough to stand up to a healthy shaving of truffles, which happens to be a classic combo.

2 tbsp butter
2 tbsp olive oil
1/2 large yellow onion, chopped
2 - 3 cloves garlic, chopped
1 large celery root, peeled and chopped into 1/2-inch cubes
salt and white pepper, to taste
4 cups vegetable or chicken stock
2 cups water
white truffles, shaved at table (optional)

Saute onion in butter and olive oil over medium heat until softened. Add garlic and cook another minute or two before adding celery root. Cook together, stirring occasionally, a few minutes. Season with salt and white pepper. Add stock and water. Simmer until celery root is soft and ready for blending, at least half an hour. Use immersion blender or food processor to blend thoroughly. Soup should be velvety smooth. Serve hot with shaved truffles on top if you got 'em.