broccoli-leak soup with lemon-chive cream

1 tbl unsalted butter
1 tbl extra virgin olive oil
2 medium leeks, white and tender green parts
only, finley chopped
1 1/2 lbs broccoli, stems peeled and sliced 1/2
inch, florets cut into 1 inch pieces
3 garlic cloves, thinly sliced
5 cups chicken stock or canned broth
salt and white pepper to taste
1/2 cup sour cream
1/4 cup grated parmesan cheese
1/4 cup snipped fresh chives
finely grated zest of 1 lemon
2 tbls lemon juice

melt butter with the olive oil in a medium saucepan over medium high heat. add the leeks and cook, stirring, until softened, about 3 minutes. stir in the broccoli, garlic and stock, season with salt and white pepper and bring to a boil. cover partially and simmer until the broccoli is tender, about 20 minutes

meanwhile, combine the sour cream, parmesan, chives, lemon zest and lemon juice in a small bowl. season with salt and white pepper. transer the soup to a blender and puree until smooth. return to the saucepan and briefly reheat. stir in half the lemon-chive cream. ladle the soup into shallow bowls and pass the remaining lemon chive cream at the table.

this serves 4 and the recipes comes from "best american recipes 2003-2004", enjoy.