2 tablespoons butter
1 onion, peeled and chopped
2 carrots, peeled and chopped
2 cloves garlic, chopped
1 15-ounce can cannellini (white) beans, drained and rinsed
1 28-ounce can crushed tomatoes
3 cups chicken broth
1 bay leaf
1 sprig of fresh rosemary, plus 1 teaspoon, minced
1/2 teaspoon red pepper flakes
3/4 teaspoon salt
1/2 teaspoon freshly ground black pepper
2/3 cup creme fraiche
Zest of one lemon
In a large soup pot, melt the butter over medium-high heat. Add the onion, carrots, and garlic and cook until the vegetables are tender, about 4 minutes. Add the beans, tomatoes, broth, bay leaf, 1 teaspoon rosemary, and red pepper flakes. Bring the soup to a boil over high heat, then reduce the heat to low and simmer for 30 minutes, covered.
Puree the soup in a blender in batches, being careful to remove and discard the bay leaf. Return the soup to a soup pot and keep warm over low heat. Season with salt and pepper.
In a medium bowl fold in the lemon zest and the remaining teaspoon of rosemary to 2/3 cup creme fraiche. To serve, ladle the soup into bowls and dollop each bowl with the lemon rosemary creme fraiche. Serve immediately.