- 8 scallions, chopped
- 1/2 stick (1/4cup) unsalted butter
- 1pound Boston lettuce (3 small heads), coarsely chopped
- 2 tablespoons water
- 1 (10-ounce) box frozen peas (preferably baby peas), thawed, or 2 cups shelled fresh peas (2 to 2 1/2 lb in pods)
- 1 1/2 teaspoons salt
- 1 tablespoon fresh lemon juice
- 2 teaspoons chopped fresh tarragon
- Cook scallions in butter in a 3-quart heavy saucepan, covered, over moderate heat, stirring occasionally, until softened, about 4 minutes. Add lettuce and water and simmer, covered, until wilted, about 5 minutes. Stir in peas and cook, uncovered, stirring, until just heated through, about 3 minutes.
- Coarsely purée in a food processor, then transfer to cleaned pan. Cook over moderate heat, stirring, until heated through, then stir in salt, lemon juice, and tarragon.