Ingredients

　　2 medium heads Boston lettuce (about 3/4 pound total)

　　3 cups chicken broth

　　1 cup water

　　2 tablespoons unsalted butter

　　freshly grated nutmeg to taste

　　Stack lettuce leaves and cut into thin shreds. In a 3-quart saucepan gently simmer lettuce, broth, and water, covered, 40 minutes. In a blender purée soup in 2 batches with butter, nutmeg, and salt and pepper to taste until smooth (use caution when blending hot liquids), transferring as blended to another saucepan. Heat soup over moderately high heat until hot.