Puréed green beans and fresh basil combine to form a compelling and sophisticated soup.
1. Melt butter in a large saucepan over medium heat. Add leeks and garlic and toss to coat. Cook until the leeks are tender. Pour in the chicken broth. Add potatoes and green beans. Bring to a gentle bubble. Cover pan and cook for 20 minutes, or until potatoes and green beans are tender. Stir in basil and cook, uncovered, for 5 minutes.
2. Pour into a blender or food processor and whirl until smooth. Return to saucepan and blend. Blend in lemon juice, salt, cayenne, savory, and cream. Warm gently, but do not allow soup to boil. Ladle into soup bowls and garnish with slices of raw mushroom, if using.