- 1 bunch leeks (about 2 pounds)
- 2 tablespoons unsalted butter
- 1 head cauliflower, cored and divided into large flowerets
- 2 1/3 cups water or vegetable stock
- 8 ounces plain Greek-style yogurt
- Salt and pepper, to taste
Halve leeks lengthwise, then slice into half-moon shapes approximately 1/2-inch-thick. In a colander, rinse thoroughly to remove any dirt between layers.
In a large pot, melt butter over medium-high heat. Add leeks and cook, stirring frequently, until tender, about 8 minutes. Do not brown.
Add cauliflower and water or stock and increase the heat to high. When soup boils, reduce heat to a simmer. Cook until cauliflower is falling-apart tender. Add yogurt and return the soup to a boil. Remove from the heat.
Using a food mill, blender or food processor, purée soup as finely as possible. Season with salt and pepper. If needed, thin to desired consistency with water, stock or milk.