vichyssoise (from ab)

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

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. Be careful that the leeks do not brown at all during this time. 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 the cream and buttermilk together, and add to soup. Stir in white pepper. Taste and adjust seasoning if desired. Serve hot or cold.