I just invented this recipe because I love rosemary and leeks together, and it seemed like a tomato-rosemary-leek soup would taste divine. And it did.
Melt butter in a large saucepan over medium heat; cook and stir leek, rosemary, and garlic until leek is tender and translucent, about 15 minutes.
Add diced tomatoes and cayenne pepper; bring to a simmer. Add minced basil; continue simmering until soup is reduced by half, about 1 hour.
Remove half of the soup and puree in a blender until smooth. Return pureed soup to the saucepan. Stir in cream to desired consistency. Season to taste with salt and ground black pepper.
Per Serving: 214 calories; protein 3.4g; carbohydrates 14.2g; fat 15.1g; cholesterol 47.5mg; sodium 765.8mg.