Ingredients

• 3/4 cup chopped onion
• 2 teaspoons unsalted butter
• 3 cups shelled fresh or frozen peas
• 2 1/2 cups low-salt chicken broth
• 2 teaspoons chopped fresh tarragon leaves
• freshly ground white pepper to taste
• 1/3 cup well-shaken buttermilk
• Accompaniment if desired: toasted French bread

Instructions

1. In a saucepan cook onion in butter, covered, over moderate heat, stirring occasionally, 5 minutes, or until tender. Add peas and broth and simmer, uncovered, 5 minutes, or until peas are tender. Stir in tarragon.
2. In a blender purée soup until smooth and pour through a coarse sieve back into pan. Heat soup over moderate heat until hot and remove pan from heat. Add white pepper and salt to taste and stir in all but 2 teaspoons buttermilk.
3. Divide soup between 2 bowls and gently spoon half of remaining buttermilk onto each serving.