Potato Leek Soup often called Vichyssoise, especially when chilled is a simple soup that makes an elegant first course.
If you’d like a flawlessly elegant presentation, press the soup through a fine mesh seive before serving to accentuate the velvety texture.
- 4 tablespoon unsalted butter (divided)
- 2 leeks, white and light green parts (halved lengthwise, cut into ½‑inch pieces and well rinsed)
- ½ teaspoon kosher salt (plus more for seasoning)
- ¼ teaspoon white pepper (or to taste)
- 1 ½ pound potatoes (peeled and cut into ½‑inch dice)
- 5–6 cup water (or low-sodium chicken stock)
- ¼‑½ cup cream (or to taste, optional)
- 1 teaspoon freshly squeezed lemon juice (optional)
- sour cream (optional, as garnish)
- minced fresh chives (optional, as garnish)
Melt 3 tablespoons butter In a good sized soup pot or Dutch oven set over medium heat. Once the butter begins to foam, but not yet color, add the leeks and sauté, stirring often, until just beginning to soften, about 3 minutes. Stir in the salt and white pepper, then continue to cook, stirring often, until the leeks are quite soft, but not yet beginning to color, about 6 minutes more.
Toss the diced potatoes in with the leeks and butter, stir to coat. Add just enough water (or stock) to cover the potatoes and the leeks. Raise the heat to high and add a couple of big pinches of salt to season the potatoes; bring the pot to a boil then turn the heat down to a simmer. Cook, stirring occasionally, until the potatoes begin to disintegrate; about ½‑hour.
Remove from heat, add the remaining 1 tablespoon butter and allow the mixture to cool somewhat. Use an immersion blender to purée to smooth velvety texture, adding a splash or two of water to achieve the desired consistency (you may alternatively use a stand blender working in batches). At this point you may gently reheat the soup and serve immediately. However, if you plan to serve it cold, chill it at least 2 hours. Either way, stir in the cream (if using, to taste) and lemon juice (if using) just before serving.
Garnish with a swirl of sour cream and a sprinkling of minced chives, if you like.