4 medium fennel bulbs
1/4 cup olive oil
1 cup chopped onion
1/2 cup diced carrot
2 tablespoons chopped fresh tarragon, plus 6 sprigs for garnish
1 teaspoon kosher salt, plus more if needed (divided)
1/4 teaspoon red-pepper flakes
1 (28-ounce) can diced tomatoes, drained well
4 cups chicken stock
2/3 cup creme fraiche (divided)
3/4 teaspoon Pernod (optional)

Cut off and discard stalks (if attached) from the fennel. Halve bulbs lengthwise, and cut out and discard tough inner cores. Chop enough fennel to yield 3 cups.

Heat the oil in a large, deep-sided pot over medium-high heat. When hot, add chopped fennel, the onion and carrot. Cook, stirring frequently, until vegetables are softened and starting to brown, for 8 to 10 minutes. Stir in the chopped tarragon, 1 teaspoon salt and the red-pepper flakes.

Add the tomatoes and the chicken stock and continue to cook at a gentle simmer (reducing heat slightly, if necessary) until vegetables are tender, for about 20 minutes.

Puree soup in batches in a food processor, blender or food mill and return soup to pot. (Or use an immersion blender to puree soup in pot.) Ladle a little warm soup into a small bowl and whisk in 1/3 cup of the creme fraiche. Then whisk this mixture into soup. Taste soup and season with salt, as needed. (Soup can be prepared 1 day ahead. Cool, cover and refrigerate. Reheat over medium heat.)

To serve, ladle 1 cup of soup into each of 6 bowls. If desired, whisk Pernod with remaining 1/3 cup creme fraiche in a small bowl. Garnish center of each serving with a dollop of creme fraiche (with or without Pernod) and a fresh tarragon sprig.

Makes 6 servings.

— Recipe from "Sunday Soup," by Betty Rosbottom.