Lemony lentil soup with greens

1. Heat oil in 6-quart pot over medium-high heat. Cook onion, stirring, 3 to 5 minutes, or until softened and translucent. Add the carrot, celery, and garlic. Cook, covered, stirring occasionally for 5 minutes or until the carrots are softened. Add 12 cups of the broth, the lentils, basil, thyme, and salt. Bring to boiling. Reduce heat to low; add kale. Cook 30 to 35 minutes, or until lentils are tender, adding additional broth if necessary. Stir in lemon juice and top with grated peel before serving. Makes 8 servings.