Active time: 15 min Start to finish: 45 min

　　

Ingredients

Makes 6 servings

　　3 tablespoons olive oil

　　1 medium onion, finely chopped

　　2 medium carrots, finely chopped

　　1 celery rib, finely chopped

　　1 1/4 cups lentils (preferably French green)

　　6 cups water

　　1 1/2 teaspoons salt

　　1/4 teaspoon black pepper

　　4 oz smoked sausage

　　1 tablespoon balsamic vinegar, or to taste

　　

Step 1

Heat 2 tablespoons oil in a 4-quart heavy pot over moderately high heat until hot but not smoking, then sauté onion, stirring occasionally, until golden brown, about 6 minutes. Add carrots and celery and cook, stirring, until softened, about 5 minutes. Add lentils, water, salt, and pepper and bring to a boil, then reduce heat to moderate and cook, covered, until lentils are tender, about 30 minutes.

　　

Step 2

While lentils are cooking, heat remaining tablespoon oil in a 10-inch nonstick skillet over high heat until hot but not smoking, then brown sausage on all sides, about 5 minutes. Cool sausage slightly on a cutting board, then cut into 1/2-inch-thick pieces. Add sausage to soup and stir in vinegar.