Ingredients:

  • 2 tablespoons unsalted butter (28 g)
  • 1 tablespoon olive oil (15 ml)
  • 3 medium leeks — white and pale green parts only, cleaned and thinly sliced (about 12 oz / 340 g)
  • 2 cloves garlic, smashed and minced (optional)
  • 2 pounds Yukon Gold or Russet potatoes, peeled and cut into 1-inch cubes (900 g)
  • 4 cups low-sodium chicken or vegetable stock (960 ml)
  • 1 bay leaf
  • 2 sprigs fresh thyme (or 1 tsp dried thyme)
  • Kosher salt and freshly ground black pepper, to taste
  • Option A (creamy): 1/2 cup heavy cream (120 ml) or 3/4 cup whole milk (180 ml) for lighter
  • Option B (lighter): 1 cup whole milk (240 ml) or additional stock (240 ml)
  • 2 tablespoons chopped fresh chives or parsley (10 g) (optional, for garnish)
  • Cracked black pepper (for garnish)
  • Crisp bacon or pancetta bits (optional garnish)
  • Small splash lemon juice, to taste (optional)

Instructions:

  1. Prepare leeks and potatoes: Trim root and dark green tops off leeks; slice the white and pale green parts and rinse thoroughly in a bowl of cold water to remove grit. Peel and cube potatoes into about 1-inch pieces.
  2. Sweat the aromatics: Melt butter with olive oil in a large heavy-bottomed pot or Dutch oven over medium heat. Add sliced leeks and a pinch of salt and cook gently until softened and translucent, about 8–10 minutes. Add garlic for the last 1–2 minutes if using.
  3. Add potatoes and stock: Add potato cubes, bay leaf, thyme, and pour in stock so ingredients are just covered. Bring to a simmer, then reduce heat and simmer gently until potatoes are very tender, about 15–20 minutes (potatoes should break apart easily with a fork).
  4. Purée the soup: Remove bay leaf and thyme stems. Use an immersion blender to purée until smooth (or cool slightly and blend in batches in a countertop blender). For extra silky texture, push the purée through a fine-mesh sieve back into the pot.
  5. Finish and season: Return to low heat and stir in cream or milk if using, warming through gently (do not boil after adding cream). Adjust thickness with extra stock if the soup is too thick. Season to taste with salt, pepper, and a small splash of lemon juice to brighten the flavors.
  6. Serve: Ladle into bowls and garnish with chopped chives or parsley, cracked black pepper, and optional bacon or pancetta bits. For chilled vichyssoise, cool to room temperature then refrigerate until cold (2–3 hours) before garnishing and serving.