📝 About This Recipe
Originally popularized by Chef Louis Diat at the Ritz-Carlton in New York, this quintessential cold soup is a masterpiece of French culinary elegance. It marries the delicate, onion-like sweetness of sautéed leeks with the creamy body of Yukon Gold potatoes, finished with a luxurious swirl of heavy cream. Served chilled, it offers a sophisticated, velvety texture and a subtle flavor profile that makes it the ultimate summer appetizer.
🥗 Ingredients
The Aromatics
- 4 tablespoons Unsalted high-quality butter (European style preferred)
- 4 large Leeks (white and light green parts only, cleaned and thinly sliced)
- 1 small Yellow onion (finely diced)
- 1 piece Garlic clove (smashed and peeled)
The Base
- 1.5 pounds Yukon Gold potatoes (peeled and cut into 1/2-inch cubes)
- 5 cups Chicken stock (low-sodium, high-quality)
- 1/4 cup Dry white wine (such as Sauvignon Blanc)
- 1.5 teaspoons Kosher salt (plus more to taste)
- 1/2 teaspoon White pepper (finely ground to maintain the white color)
- 2 pieces Fresh thyme sprig (tied together with kitchen twine)
The Finish
- 1 cup Heavy cream (chilled)
- 1 teaspoon Lemon juice (freshly squeezed for brightness)
- 3 tablespoons Fresh chives (finely minced for garnish)
- 1/4 cup Crème fraîche (for a decorative swirl)
👨🍳 Instructions
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1
Melt the butter in a large, heavy-bottomed Dutch oven or stockpot over medium-low heat until foaming.
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2
Add the sliced leeks and diced onion to the pot. Sauté gently for 10-12 minutes, stirring frequently. It is vital not to let them brown; you want them translucent and completely soft.
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3
Add the smashed garlic clove and cook for another 60 seconds until fragrant.
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4
Deglaze the pan with the white wine, scraping up any bits from the bottom, and let it reduce by half.
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5
Stir in the cubed Yukon Gold potatoes, ensuring they are well-coated in the buttery leek mixture.
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6
Pour in the chicken stock and add the thyme sprigs. Increase the heat to medium-high and bring the liquid to a gentle boil.
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7
Once boiling, reduce the heat to low, cover partially, and simmer for 25-30 minutes, or until the potatoes are very tender and fall apart when pierced with a fork.
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8
Remove the thyme sprigs and discard. Let the soup cool slightly for about 10 minutes before blending.
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9
Using a high-speed blender, process the soup in batches until it is absolutely smooth. Start on low speed and gradually increase to high to ensure a silky texture.
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10
For a true professional finish, pour the blended soup through a fine-mesh sieve (chinois) into a clean bowl, pressing on the solids with the back of a ladle.
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11
Whisk in the heavy cream and lemon juice. Season with kosher salt and white pepper. Note: Cold dulls saltiness, so you may need slightly more than you think.
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12
Cover and refrigerate for at least 4 hours, though overnight is best to allow the flavors to marry and the soup to become ice-cold.
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13
Before serving, check the consistency. If it has thickened too much in the fridge, whisk in a tablespoon or two of cold milk or stock to loosen it.
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14
Ladle into chilled bowls. Garnish with a small dollop of crème fraîche and a generous sprinkle of fresh chives.
💡 Chef's Tips
Clean your leeks thoroughly by soaking sliced rounds in cold water to remove all grit. Use Yukon Gold potatoes rather than Russets for a naturally creamier, less grainy mouthfeel. Always use white pepper instead of black to keep the soup's appearance pristine and ivory-white. Never boil the soup after adding the cream, as this can affect the delicate chilled texture. Taste the soup again right before serving; chilling reduces the intensity of seasoning, so a final pinch of salt is often necessary.
🍽️ Serving Suggestions
Pair with a crisp, chilled glass of Sancerre or Chablis. Serve alongside a warm, crusty French baguette with salted butter. A side of smoked salmon tartines provides a salty contrast to the creamy soup. For a light lunch, pair with a simple butter lettuce salad dressed in a champagne vinaigrette. Top with a few drops of high-quality truffle oil for an extra layer of luxury.