- 2 medium shallots, chopped
- 1 teaspoon olive oil
- 1 (4-ounce) boiling potato, peeled and cut into 1/2-inch pieces
- 1 teaspoon salt
- 3 1/2 cups water
- 1 pound frozen baby peas (3 1/2 cups), thawed
- 1 tablespoon crème fraîche or sour cream, either one mixed with 1 teaspoon water
- Cook shallots in oil in a 3-quart heavy saucepan over moderate heat, stirring, until softened, about 2 minutes. Add potato and salt and cook, stirring, 2 minutes. Add water and simmer, covered, until potato is tender, about 15 minutes. Add peas and simmer, uncovered, 2 minutes.
- Purée in batches in a blender (use caution when blending hot liquids), then force through a very fine sieve into a saucepan. Reheat soup and season with salt and pepper.
- Drizzle servings with crème fraîche.