Middle Eastern Vegetable and Lentil Soup

Heat oil in a large pot over medium-high heat. Add onion and celery. Cook until lightly browned, stirring occasionally, 5 to 10 minutes. Add garlic and cook another minute or 2, stirring constantly. Add broth, water, and lentils and bring to a boil, about 5 minutes.

Add eggplant to the soup and return to a boil. Reduce heat, cover, and simmer 15 minutes more. Stir in zucchini and tomato and return to a boil. Reduce heat, cover, and simmer until zucchini are tender but still bright, about 5 minutes more. Remove soup from heat and stir in lemon zest and juice. Season with salt and pepper.