Sweet Potato Soup with Buttered Pecans

¾ c. onion (finely chopped)
1 c. leeks (washed, drained and finely chopped)
2 large garlic cloves (minced)
3 large carrots (sliced thin)
1 bay leaf
3 T. melted butter or margarine
2 lbs. sweet potatoes (peeled, halved lengthwise, sliced thin)
1 russet potato (peeled, halved lengthwise, sliced thin)
5 c. chicken broth (plus additional quantity to thin soup, if desired)
¾ c. dry white wine
1 ½ c. water
Sour cream (for topping)

Buttered Pecans:
¾ c. pecans (chopped)
2 T. unsalted butter

Cook the onion, leek, garlic, carrots and bay leaf in butter over moderate heat, stirring until the vegetables are softened. Add the sweet potatoes, russet potato, broth, wine and water. Cover and simmer the mixture for 15-20 minutes, or until the potatoes are very tender. Discard the bay leaf. In a blender, puree the mixture in batches until very smooth and transfer each batch into one large pot. Add additional broth to pot to thin soup (if desired), and season with salt and pepper to taste.

Buttered Pecans
In a skillet, cook pecans in butter (salt to taste) over moderate heat, stirring occasionally. Stir for 10 minutes or until pecans are golden brown, then transfer to paper towel to drain. Top each bowl of soup with a dollop of sour cream and buttered pecans before serving.