Begin several hours ahead and use a good brie.
1/2 c. unsalted butter
8 lg. leeks (white part only) finely chopped
4 c. chicken stock
1/2 c. flour
4 c. half and half
1 1/2 lb. Brie cheese, Well chilled,
Cut into small cubes with rind on
Salt and pepper
2 tbsp. fresh chives or, minced fresh parsley

Melt 1/4 cup butter in heavy deep skillet over medium heat. Add leeks and cook until translucent, stirring frequently about 4 minutes. Add 4 cups stock and bring to boil. Reduce heat, cover and simmer until leeks are tender, about 25 minutes. Puree mixture. Melt remaining 1/4 c. butter in heavy non-aluminum saucepan over medium heat. Add flour and stir 2 minutes. Blend in half and half 1 cup at a time, whisk until smooth. Add 1/4 of cheese and blend until smooth and melted.

Repeat with remaining cheese in batches. Strain soup and return to saucepan. Mix in leek puree. (Can be prepared 8 hours ahead. Cool, cover and refrigerate) Rewarm soup over low heat. stir constantly. Thin with more stock in necessary. Garnish with pepper and fresh chives or parsley