Carrot & Sweet Potato Vichyssoise

Prep Time : 30 minutes     Cooking time : 30 minutes       Chilling time : 2 to 3 hours      Makes 6 servings

3          tablespoons butter  or margarine
2          small leeks  , halved length-wise , , thoroughly washed  and sliced
1/2        teaspoon ground nutmeg
2           medium-size  sweet potatoes , peeled  and cut into 2-inch  chunks
2           medium-size carrots  , peeled  and cut  into 2-inch  chunks
4          cups Rich Chicken Stock  or canned  low-sodium  chicken broth
1-1/2    cups buttermilk
salt  and freshly  ground pepper  to taste (optional)
1          cup heavy cream
2          tablespoons  snipped  chives

1 .    In a medium-size  saucepan , over  moderate  heat , melt butter  . Add leeks  and nutmeg  and saute  , stirring  occasionally  until tender ,  about 5 minutes .
2 .    Add sweet potatoes  , carrots  and stock  and bring  to a boil over  high heat . Reduce  the heat  to low  and simmer  uncovered  until the sweet potatoes  and carrots  are tender  , 15 to 20 minutes . Remove  from  the heat  and cool 10 minutes .
3 .       Working in batches  , puree  the mixture  in a blender   at high  speed  or in a food processor  . Stir  in buttermilk  , salt  and pepper  (optional). If soup seems  too thick . thin  with  a little additional stock or buttermilk .
4 .        Tranfer  to a large  bowl , cover  and refrigerate  2 to 3 hours . When ready to serve  , spoon into serving bowls  . For a fancy  presentation  , paint the surface  with cream , sprinkle  with chives  if desired .