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Leek Potato Soup

This classic recipe creates a creamy, comforting leek and potato soup. Leeks are slow-cooked in butter, then simmered with diced potatoes in vegetable broth. The mixture is pureed until smooth and finished with heavy cream and buttermilk for richness and tang.
Print Recipe
Prep Time 25 minutes
Cook Time 1 hour 15 minutes
Total Time 1 hour 40 minutes
Course lunch/dinner
Cuisine French
Servings 6 people
Calories 1994.2 kcal

Equipment

  • 1 Large Saucepan Approximately 6-quart capacity
  • 1 Immersion Blender For pureeing directly in the pot
  • 1 Cutting Board
  • 1 Chef's knife
  • 1 Ladle For serving

Ingredients
  

Main

  • 1 pound leeks cleaned and dark green sections removed, approximately 4 to 5 medium
  • 3 tablespoons unsalted butter
  • Heavy pinch kosher salt plus additional for seasoning
  • 14 ounces approximately 3 small, Yukon gold potatoes, peeled and diced small
  • 1 quart vegetable broth
  • 1 cup heavy cream
  • 1 cup buttermilk
  • 1/2 teaspoon white pepper
  • 1 tablespoon snipped chives

Instructions
 

  • Chop the leeks into small pieces.
  • In a 6-quart saucepan over medium heat, melt the butter. Add the leeks and a heavy pinch of salt and sweat for 5 minutes. Decrease the heat to medium-low and cook until the leeks are tender, approximately 25 minutes, stirring occasionally.
  • Add the potatoes and the vegetable broth, increase the heat to medium-high, and bring to a boil. Reduce the heat to low, cover, and gently simmer until the potatoes are soft, approximately 45 minutes.
  • Turn off the heat and puree the mixture with an immersion blender until smooth. Stir in the heavy cream, buttermilk, and white pepper. Taste and adjust seasoning if desired. Sprinkle with chives and serve immediately, or chill and serve cold.

Notes

Ensure leeks are meticulously cleaned, as dirt can hide between the layers. Sweat the leeks slowly over low heat; this gentle cooking brings out their sweetness without browning. Don't rush the potato simmering phase; they must be very tender to achieve a truly smooth soup when pureed. The addition of buttermilk provides a pleasant tang that balances the richness of the heavy cream and butter. Taste and adjust seasoning after adding the dairy, as liquids can dilute saltiness. For a thinner soup, add a little more broth or hot water after pureeing.