This spinach and lentil soup is a hearty and healthy soup that is perfect for a cold day. The soup is made with lentils, spinach, carrots, celery, and onions, which adds flavor and nutrients. The lentils add protein and fiber, while the spinach adds vitamins and minerals. This soup is easy to make and can be prepared ahead of time. Serve it with a slice of whole wheat bread for a complete and nutritious meal.