Leek and Potato Soup
While you can use whatever dairy you have on hand (see above), I’m pretty keen on using Yukon Gold potatoes in the soup – which give you the perfect balance of starch to moisture, yielding a silky smooth soup. If you’re in a possession of a Vitamix (a pricey pricey gadget that is worth its weight in gold), you will wind up with the kind of texture you get at three-star Michelin restaurants. Given my preoccupation with all things baby right now, I just use my stick blender and leave a few errant pieces of potato and leek in, and it’s still pretty good. Last, but certainly not least, don’t forget to fish out the parm rind before blending!
1 pound leeks, white and light green parts only
3 tablespoons unsalted butter
1 tablespoon olive oil
Heavy pinch kosher salt, plus additional for seasoning
1 pound, approximately 2 medium, Yukon gold potatoes, peeled and diced small
1 quart chicken or turkey stock
1 (3-inch) rind Parmigiano-Reggiano cheese
1 cup heavy cream
1 cup buttermilk
1/2 cup finely grated Parmigiano-Reggiano (optional)
1/2 teaspoon freshly grated white pepper
1 tablespoon snipped fresh chives (optional)
Thinly slice the leeks and clean in 2 changes of water bath. [Place leeks in a large bowl and fill with cold water. Let stand 5 minutes so all the dirt/grit settle on the bottom. Gently, using a spider, lift the leeks out of the water and onto an absorbent towel. Repeat once or twice more, depending on how dirty the leeks are.]
2. In a large soup pot set over medium heat, melt the butter and oil. Add the leeks and a generous pinch of salt and sweat leeks, stirring, for 5 minutes. Decrease the heat to medium-low and cook until the leeks are tender, approximately 20 minutes, stirring occasionally.
3. Add the potatoes, stock, and cheese rind, increase the heat to medium-high, and bring to a boil. Reduce the heat to low, cover, and gently simmer until the potatoes are soft, approximately 30 minutes.
4. Turn off the heat, remove and discard the cheese rind, and puree the soup with an immersion blender until smooth (if you want to step it up texture-wise, use a good standing blender, such as a Vitamix). Stir in the heavy cream, buttermilk, cheese, if using, and white pepper. Taste and adjust seasoning if desired. Sprinkle with chives, if using, and serve immediately.