Saanich Green Market Lentil Soup

At the April 2nd market we served homemade lentil soup. There were several requests for the recipe. Here goes!
(from the cookbook- Middle Eastern Cooking by Rose Dosti.)

1 cup lentils
1/4 cup olive oil
2 medium onions, chopped
2 medium carrots, sliced
2 garlic cloves, minced
1 celery stalk, thinly sliced
8 cups soup broth
3 parsley sprigs
Salt and pepper to taste
1 Tablespoon lemon juice or vinegar
1/2 tsp ground cumin

Rinse lentils several times. Set aside to drain. Heat olive oil in a large sauce pan. Add onions and garlic. Sauté until onions are tender. Add carrots and celery. Cook 10 minutes over low heat. Add lentils, broth, parsley, salt and pepper and cumin. Bring to a boil. Reduce heat and cover. Simmer over low heat for 1 to 1/2 hours or until lentils are tender and broth is slightly thickened. Remove parsley sprigs and discard. Add lemon juice just before serving, makes 6 servings.