Ingredients

• 1 tablespoon unsalted butter
• 1 tablespoon extra-virgin olive oil
• 2 medium leeks, white and tender green parts only, finely chopped
• 1 1/2 pounds broccoli, stems peeled and sliced 1/2 inch thick, florets cut into 1-inch pieces
• 3 garlic cloves, thinly sliced
• 5 cups chicken stock or canned low-sodium broth
• Salt and freshly ground white pepper
• 1/2 cup sour cream
• Finely grated zest of 1 lemon
• 2 tablespoons fresh lemon juice
• 1/4 cup snipped chives
• 1/4 cup grated Parmesan cheese

Instructions

1. In a medium saucepan, melt the butter in the olive oil. Add the leeks and cook over moderately high heat, 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, 20 minutes.
2. Meanwhile, in a small bowl, stir the sour cream with the lemon zest, lemon juice, chives and Parmesan. Season with salt and white pepper.
3. Transfer the soup to a blender and puree in batches until smooth. Stir in half of the lemon-chive cream. Ladle the soup into shallow bowls and serve the remaining lemon-chive cream on the side.

Serves 4 people.