Serves 4
4 large leeks, about 2½ pounds, white and light green parts only
3 tablespoons unsalted butter
1 teaspoon sea salt
Freshly ground black pepper
2 pounds Yukon gold potatoes or yellow potatoes, chopped
3 garlic cloves, grated
8 cups vegetable broth
3 fresh thyme sprigs, bundled
1/4 cup chopped fresh dill
1 cup milk or heavy cream
1 tablespoon fresh lemon juice, optional
Chopped fresh chives, for garnish
Make the soup: Chop the white and light green parts of the leeks. Wash well.
Heat the butter in a large pot or Dutch oven over medium heat. Add the leeks, salt, and several grinds of pepper and cook for 8 to 10 minutes, stirring occasionally, or until the leeks are soft. If the leeks start browning before they soften, reduce the heat.
Add the potatoes, garlic, broth, and thyme and simmer for 20 minutes, or until the potatoes are very soft. Remove the thyme, then use an immersion blender or transfer the soup to an upright blender to blend until smooth. Return the soup to the pot and stir in the milk. Season to taste, adding the lemon juice, if desired.
Garnish with chives, dill and serve.