This soup keeps very well. Refrigerate up to 5 days, or freeze in airtight containers up to 3 months. Adjust the broth accordingly to desired thickness of the soup.
Heat 1 Tbsp. oil in a large nonstick saucepan over medium-high heat; add the ground turkey and cook until browned. Remove from pan and set aside.
In the same pan, add the remaining 1 Tbsp. olive oil, and add the carrot, onion and celery; cook and stir for about 5 minutes until the onions are golden. Stir in the garlic for 1 minute.
Remove to a large pot and add the onion mixture, ground turkey, broth and tomatoes; bring to a boil over high heat. Adjust the broth according to desired consitency of the soup.
Add barley, mushrooms, salt and pepper; cover, reduce heat to medium-low and simmer, stirring occasionally, until barley is almost tender, about 40 minutes.
Stir in zucchini, corn, and spinach; cover and cook until barley and zucchini are tender, about 5 minutes. Remove from heat and stir in basil. Season to taste, if desired. Serve!