It was seven degrees here this morning when we woke up. Seven degrees! I would complain, but when I called my mother, she told me her thermometer read seven below. She tends to stop by here, so I have a feeling I'd better keep mum. Anyhow, the good news is that it's now up to a balmy 16.3, and I have tested the waters and found that with two pairs of sweatpants, a turtleneck, and a sweater on, it is warm enough to make soup.
Those specimens up there are a major component of the soup I'm making today, which is the same soup we've been eating now for about a week straight. It's a potato-leek-celeriac soup that I found in an old Bon Appetit cookbook—Entertaining with Style, circa 1996—and it's amazing.
(Celeriac, in case you're not familiar with it, is the knobby, gnarly root that grows under a certain variety of celery. Unlike most celery varieties, it's grown mainly for what's underground, but you can also use the leaves and stalks as you normally would. My friend Tracy grew a bunch in her greenhouse, and we are addicted.)
If I had to pick one word to describe this soup, I would tell you that it is velvety. The celeriac gives it a creaminess that is somehow different—somehow more subtle and more refreshing than the heavy, overdone richness that you find in most potato-leek soup recipes—and that, I think, is what makes it so wonderful. It has comfort food written all over it, but it also has tang and pizazz. I like that.
I also like that it cooks for a while, which means there's a stove burner on, which warms the house up. I have a recipe for Oatmeal Sandwich bread marked, which bakes at 400 degrees, and I'm thinking of making that too. But I'm starting with soup.
The original recipe for this soup actually called for twice as much celeriac as potato, but even as a celeriac lover, I thought that was too much. I swapped the ratios, so that the celeriac to potatoes was 1 to 2, and I thought that was perfect. Also, the original recipe called for olive oil, not butter, but I ended up adding the butter for creaminess later on, so the next time around I never bothered with the olive oil at all. In a soup like this, I think you need the creaminess that butter adds. And for toppings, the original recipe recommended parsley and orange zest and red onions, but we stuck with just the red onions, and I thought they were more than enough. Soup this good doesn't need dressing up. Oh! and it serves 3.
3 tablespoons butter
1 leek, washed and thinly sliced (white and light green parts only)
1 and 1/2 cups chicken or vegetable stock, preferably homemade
1/2 pound celeriac, peeled and cut into 1/2-inch pieces
1 pound potatoes, peeled and cut into 1/2-inch pieces
1 cup whole milk
freshly cracked pepper
1/2 red onion (optional)
Heat up the butter in a medium, heavy-bottomed pot. Add the leek and sauté for 5-8 minutes, or until it starts to get tender. Season with about 1 teaspoon salt (unless you are using a salty broth, in which case you should wait and season later on). Add the stock, celeriac, and potatoes and bring to a boil. Turn the heat down, cover, and simmer for about 45 minutes, or until the vegetables are soft.
Use an immersion blender or food processor to puree the soup. Add enough milk to thin the soup to your liking, taste the soup, and add salt and pepper as needed. Simmer for another few minutes to let the flavor deepen, then serve hot. We like it with a generous handful of finely chopped red onions on top.