Vichyssoise

Instructions

1. Prepare the leeks
   Cut off the dark green tops and roots of the leeks. Slice them in half lengthwise and rinse thoroughly under cold water to remove any sand or dirt between the layers. Slice the cleaned leeks thinly.
2. Sauté the vegetables
   In a large, heavy-bottomed pot, melt the butter with olive oil over medium heat. Add the leeks and onion, and cook gently for about 10 minutes until soft but not browned, stirring occasionally.
3. Simmer the soup
   Add the potatoes and chicken broth to the pot. Bring to a boil, then reduce heat and simmer, partially covered, for about 25 minutes or until the potatoes are very tender when pierced with a fork.
4. Purée the soup
   Remove the pot from heat and allow to cool slightly. Purée the soup using an immersion blender until completely smooth. Alternatively, transfer the soup in batches to a blender, being careful with the hot liquid.
5. Add dairy and seasonings
   Stir in the heavy cream and milk. Season with salt, white pepper, and nutmeg if using. Mix well and adjust seasonings to taste.
6. Chill thoroughly
   Transfer the soup to a large bowl and let it cool to room temperature. Cover and refrigerate for at least 4 hours or overnight until completely chilled.
7. Serve the Vichyssoise
   Before serving, taste and adjust the seasoning if necessary, as chilled soups often need additional seasoning. If the soup is too thick, thin it with a little more cold milk. Ladle into chilled bowls and garnish with finely chopped chives.