Ingredients:

1 1/2 cups chopped onion
1 tablespoon unsalted butter
6 cups shelled fresh or frozen peas
5 cups low-salt chicken broth
1 tablespoon chopped fresh mint leaves
Freshly ground white pepper
2/3 cup well-shaken buttermilk
Toasted French bread, as an accompaniment

Cooking Recipe:

In a saucepan cook onion in butter, covered, over moderate heat, stirring occasionally, 5 minutes, or until tender. Add peas and broth and simmer (cook slowly) , uncovered, 5 minutes, or until peas are tender. Stir in mint.

In a blender puree 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 4 teaspoons buttermilk.

Divide soup between 4 bowls and gently spoon remaining buttermilk onto each serving.