As the days grow shorter and the colder weather begins to seep through the windows and into my bones I make pot after pot of soup. This luscious cauliflower and leek soup is one of my favorites. Possessing a milder onion flavor than either white or yellow onions leeks are one of my favorite aromatics as they don't overpower the other flavors in this soup.
As a child I only ate Mom's chicken soup, tomato soup (with a grilled cheese... mmmm), and New England clam chowder. I don't recall the first time I had potato-leek soup but I do remember how magical I thought it was. After tasting that creamy, smooth, luscious soup pureed vegetable soups became some of my favorites. I distinctly recall one afternoon living in Bologna when the Mercato delle Erbe, the city's central produce market, was simply overflowing with leeks.
I purchased a few particularly beautiful specimens with long, firm, white stalks like a swan's neck. Riding home on the lumbering orange city bus, hanging onto the overhead strap and keeping my balance as best I could, the bag kept bumping against my legs. The rhythm helped keep my mind off of the cold seeping damply through every fiber of my being. I climbed the stone stairs to the tiny attic apartment I shared with my roommate and began to clean the leeks.
Since leeks are grown with dirt mounded around them to prevent the stalks from turning green and fibrous the dirt gets trapped between the layers and must therefore be cleaned thoroughly before use. My roommate Martina came in and immediately began laughing. She was completely incredulous that I would make "una zuppa di porri" (leek soup). She wasn't laughing when I served her a fragrant bowl of enticing potato-leek soup with wisps of steam curling off the bowl.
Over the years I've substituted cauliflower for much of the potato in this recipe. I still use russet (i.e. baking) potatoes to add body to the soup instead of using a roux to thicken it. While the black truffle oil is optional I definitely urge you to use it if you can find it in your local stores. A little goes a very long way and it adds a magnificent aroma and flavor to soups, egg dishes and many other vegetable preparations. I use a teaspoon almost every time I make anything with mushrooms to enhance the flavors.
An immersion blender is also a great thing to have for this recipe. I make a wide variety of pureed soups during the winter months and keep my immersion blender very busy. The model I use is the Cuisinart SmartStick which I've had since 2008 and have taken it with me on three moves. I've never had a problem with it.
Cauliflower Leek Soup ~ serves 6-8
5 cups cauliflower, fresh or frozen
2.5 cups leek, thinly sliced
2 cups russet potato, peeled and rough chopped
1 cup celery, diced
1/2 cup carrot, diced
40 oz chicken or vegetable stock
1 T olive oil
1 bay leaf
salt, pepper & nutmeg to taste
1 tsp black truffle oil, such as La Tourangelle
Heat a large soup pot over medium heat. Add olive oil and heat gently. Add sliced leeks, diced celery and carrots and saute until beginning to turn translucent. Add cauliflower and potatoes, stir to coat in diced vegetables. Add stock and bay leaf. Let simmer, uncovered, for 30-40 minutes or until potatoes are tender.
Remove pot from heat and discard bay leaf. Using your immersion blender, or working in batches with a stand blender, puree the soup to your desired consistency. Season to taste with salt, pepper, and freshly grated nutmeg. Stir in a teaspoon of black truffle oil to the pot and serve hot. If you like you can drizzle a little heavy cream into the bowls before serving or top with some fried leeks as I've done here.