This is Alis all-time favorite soup, and its delicious! This was the first dish she cooked for date night. Tortilla soup is fortified with spices and herbs. It is also thickened with tortillas, which is a great technique to know. Techniques for soup thickening vary from roux, to rice, to this technique of using tortillas. Still other soups are thickened with bread or potato, but the tortillas give it a full mouthfeel. Its a great cooking lesson that yields a delicious dish.