Ingredients

　　2 russet (baking) potatoes

　　2 medium carrots, cut into 1/4-inch dice

　　2 celery ribs, cut into 1/4-inch dice

　　3 garlic cloves, chopped fine

　　1 medium onion, chopped fine

　　2 tablespoons unsalted butter

　　1 pound lentilles du Puy* (French green lentils), picked over and rinsed (about 2 cups)

　　8 cups low-salt chicken broth

　　Garnish: chopped fresh parsley leaves

　　*available at specialty foods shops and some supermarkets

　　Peel potatoes and cut into 1/4-inch dice. In a 5- to 6-quart heavy kettle cook potatoes, carrots, celery, garlic, and onion in butter over moderate heat, stirring frequently, until onion is softened, about 4 minutes. Add lentils, broth, and salt and pepper to taste and simmer, uncovered, stirring occasionally, 45 minutes, or until vegetables are tender and soup is thickened. Serve soup garnished with parsley.