Celeriac Soup with Truffle Oil

Winter doesn’t bring the shining stars of the produce world that spring, summer and fall do. No asparagus. No strawberries. No heirloom tomatoes. Not a whole lot of anything, really. Just a bunch of boring old root vegetables.

Luckily, when the weather turns cold and grey, root vegetables start to sound more appealing, as does standing over a warm stove coaxing them into a crispy saute or satiny soup. Unfortunately, when we get our obligatory mid-winter California heatwave, the one that tricks us into thinking, winter is over! wow, that was fast!, the produce availability does not magically change accordingly, and I find myself wondering what to eat. Salad again? An orange? I’ve had a celery root from our box sitting in the fridge for the past two weeks, but couldn’t bring myself to do anything with it, as the weather has been downright summery.

Yes, I am aware that anyone not living in California currently wants to punch me in the head.

But before you do, know that as of this week, we spoilt Californians are back to our regularly-scheduled winter, and that today I slogged home from work in freezing (ok, 50º) rain and wind, feeling pretty sorry for myself. But the thought of a bowl of warm soup awaiting me for supper made everything better.

As did the thought of our newest and orangest family member, and the way he would probably curl up on my laptop to ‘help’ me write this post.

I had never tasted celery root before I signed up for a CSA several years ago. They aren’t exactly attractive-looking, and the name doesn’t do anything for their reputation. But cook them up with lots of butter, sweet leeks and potatoes, and their earthy, clean flavor reminiscent of truffles comes forward in a silky nappe of a soup. If the thought of eating beige root soup makes you feel deprived, just drizzle some truffle oil and a scatter of celery leaves over the top, and I reckon you will change your mind. This soup is nothing short of luxurious, and I wouldn’t hesitate to serve it to a discerning guest. I got a small bottle of white truffle oil at Rainbow a few years ago for less than $10, and it has proved a useful topping for tarts, soups and roasted vegetables, adding a tantalizing burst of umami to any dish.

Sometimes when I’m feeling particularly homesteader-ish, I save vegetable trimmings in a large, ziploc baggie in the freezer to make into soup stock later on. Good candidates for this are neutral-tasting vegetables: potato, carrot, onion and parsnip peels and trimmings, celery trimmings and leaves, several parsley stems, and leek leaves and roots. Make sure your veg is clean, and not older than you would want to eat (i.e. browning or rotting). When you get a good bag full, put everything in a stock pot with water to cover, add a bay leaf or two, some thyme sprigs if you got ’em, and 10 or so peppercorns. Cover and bring to a boil, then simmer 20 minutes. Strain, and you’ve got yourself some stock. If you don’t want to use it all, stick it in the freezer for a rainy day, when you want to make soup but don’t want to get out of your jammies.

Rooting for roots:

Potato, Spring Onion and Turnip Potage
Spiced Sweet Potato Oven Fries
Oven-Roasted Potatoes and Parsnips

One year ago:

(Vegan) Chocolate Coconut-Milk Tapioca Pudding

Creamy Celeriac Soup with Truffle Oil

Makes 6 servings

You can make a quick stock with the trimmings of the leeks, celery root and potatoes, and 8 cups of water. Throw in a carrot and an onion, in large chunks, if you like, for a bit more flavor. Or use a good quality, prepared vegetable or chicken stock. If you use stock or bouillon with salt, omit the salt in the recipe and add some at the end to taste, instead.

To easily wash leeks, cut them as directed below, then place them in a large bowl and fill with cool water. Swish the leeks around to loosen the slices, then let sit for a few minutes. Any sand or silt will settle to the bottom. Lift the leeks out with your fingers, shaking off excess water before adding them to the pot.

3 tablespoons unsalted butter
3 medium leeks (white, light and bright green parts), halved lengthwise, then sliced crosswise 1/4″ thick, washed (see note above)
12 ounces yellow potatoes (such as Yukon Gold or Yellow Finn, about 3 lemon-sized potatoes), peeled, in 3/4″ chunks
1 pound celery root (1 large), peeled, in 3/4″ chunks
6 cups salt-free vegetable stock (preferably homemade, see note above)
1 bay leaf
1 teaspoon salt
1/4 – 1/2 cup half and half (or milk or heavy cream)
truffle oil (or walnut, porcini, or super-good olive oil), for drizzling
celery leaves, torn (or chervil, parsley or chives), for sprinkling

Melt the butter in a large soup pot or dutch oven. Add the leeks and saute while you prepare the potatoes and celery root. Add the vegetables to the leeks as you work, then give everything a turn to coat it in the butter, and add the stock, bay leaf and salt. Partially cover the pot and bring to a boil, then reduce the heat to maintain a simmer.

Cook for 20 – 30 minutes, until the potato and celery root are soft. Puree the soup smooth with an immersion blender if you’ve got one, or in a blender, carefully, in batches (don’t fill the blender more than halfway full, and hold the lid closed with a thick towel, or cool the soup to room temp first). Add enough half and half to thin the soup to your liking.

Serve the soup hot, with a drizzle of truffle oil and a sprinkle of celery leaves. The soup keeps well in the fridge for up to several days.