Marie's tortilla soup recipe is a very easy slow cooker soup, and it is loaded with flavor. The soup takes just minutes to put the ingredients together in the slow cooker and then it cooks hands-free for about 7 hours. This is the perfect soup to come home to on a chilly fall or winter evening. Go about your daily routine while your dinner cooksThe soup can easily be adjusted by adding more vegetables for extra nutrients, color, and flavor. Whole kernel corn is an excellent choice; add about 1 cup of frozen corn kernels to the soup along with the tomatoes. A diced carrot is a good addition as well or add about 1 cup of canned black beans or pinto beans. Some other flavor possibilities are sweet red or green bell pepper, diced celery or 2 to 3 tablespoons of freshly squeezed lime juice.