01In a 3.5-to 5-quart slow cooker, combine the beans, corn, barley, tomatoes, mushrooms, onion, carrot, celery, garlic, Italian seasoning, salt, and pepper. Pour chicken broth over the mixture and stir to combine. Cover and cook on low for approximately 8 ½ hours (or on high for approximately 4½ hours).
02 Near end of cooking time, whisk the cornstarch into milk. Stir the milk mixture into the slow cooker until well blended. (If the cooker is on low, turn it to high.) Continue cooking for approximately 20 minutes or until the soup has thickened.
03To serve, ladle the soup into bowls. Sprinkle each serving with fresh parsley and Parmesan cheese.
04 For stove top method, using a soup pot, add vegetable oil and sauté the onion, mushrooms, celery, carrot, garlic, Italian seasoning, salt, and pepper for approximately 5 minutes or until crisp-tender.
05 Stir in the beans, corn, barley, tomatoes, and chicken broth. Cover and cook until the barley is tender, approximately 30 minutes.
06 Whisk the corn starch into the milk, then stir into the soup. Let simmer, stirring frequently, for 5 minutes or until the soup is slightly thickened and creamy. Sprinkle each serving with fresh parsley and cheese.