Traditional Potato Leek Soup Recipe

Prepare vegetables

Trim off the dark green tops of the leeks, halve lengthwise, and rinse thoroughly under cold water to remove grit. Thinly slice the white and light-green parts. Peel and cube the potatoes into roughly 1/2-inch pieces so they cook evenly. Finely dice the onion and mince the garlic. Chop chives and set aside for garnish.

Sweat aromatics

In a large heavy-bottomed pot over medium heat, melt the butter with the olive oil. Add the diced onion and a pinch of salt. Cook, stirring occasionally, until the onion is translucent and soft, about 5–7 minutes. Add the sliced leeks and continue to cook, stirring occasionally, until the leeks are soft and beginning to wilt, about 6–8 minutes. Add the minced garlic and cook for 30–60 seconds until fragrant.

Add potatoes and stock

Add the cubed potatoes to the pot and stir to coat with the butter and vegetables. Pour in the stock until the vegetables are just covered (about 1 L). Add the bay leaf and thyme sprigs. Bring to a gentle boil over medium-high heat, then reduce to a simmer. Cover partially and simmer until the potatoes are very tender, about 15–20 minutes.

Remove herbs and blend

Remove and discard the bay leaf and thyme sprigs. For a smooth soup: use an immersion blender directly in the pot and puree until silky. For a chunkier texture: remove about one-third of the cooked potato-leek mixture to a blender, puree until smooth, and return it to the pot. Be careful with hot liquids when using a blender (vent the lid slightly and pulse).

Adjust texture and season

Stir in the milk or cream and heat gently over low heat until warmed through—do not boil. Taste and adjust seasoning with additional salt and freshly ground black pepper. If desired, stir in the optional teaspoon of lemon juice to brighten flavors.

Ladle the soup into bowls. Garnish each bowl with a sprinkle of chopped chives and the optional crumbled bacon or pancetta. Serve hot with crusty bread.