Leek Potato Soup

This is a great soup recipe that I adapted from Alton Brown. I was cruising the Food Network's sight, www.foodtv.com, looking for a simple recipe when I found this one. I added a few things and changed the vegetable cooking times (he seemed to cook the veggies much longer than actually needed). The soup turned out very flavorful and silky and is one I would make again.

Leek Potato Soup

1 lb. leeks, cleaned and dark green sections removed, chopped into small pieces
3 Tbsp. unsalted butter
Heavy pinch of kosher salt
2 cloves garlic, chopped
1 lb. Yukon gold potatoes, peeled and small diced
1 qt. vegetable broth
1 cup half and half
1 cup buttermilk
1/2 tsp. white pepper
1 Tbsp. flat leaf parsley, chopped

In a 6-qt. saucepan over medium heat, melt butter. Add the leeks and a heavy pinch of salt and sweat for 5 minutes. Decrease heat to medium-low and cook until leeks are tender, 10-15 minutes, stirring occasionally.
Add garlic, potatoes and broth, increase heat to medium-high and bring to a boil. Reduce heat to low, cover and gently simmer until potatoes are soft, about 15 minutes.
Turn off heat and puree mixture with an immersion blender until smooth. Stir in half and half, buttermilk and white pepper. Sprinkle with parsley and serve immediately.