1 medium onion, chopped
2 celery stalks, chopped
2 small carrots, chopped
1/4 cup olive oil
2 garlic cloves, chopped
2 cups diced tomatoes
2-1/4 cups lentils
8 cups chicken or beef stock
1 head escarole, chopped
Salt and pepper
1/2 cup grated Parmesan cheese

Directions:

In a large saucepan over medium heat, cook the onion, celery, and carrots in olive oil about 10 minutes.  Add the garlic and cook 1 more minute.  Add the tomatoes, bring to a simmer, and cook 10 minutes to reduce the liquid.  Add the lentils and stock and bring to a simmer.  Reduce the heat to low and cook, uncovered, about 30 minutes.  Add the escarole, salt and pepper to taste, and cook until lentils are tender, 35-45 minutes.  Ladle into individual bowls and sprinkle with Parmesan cheese.