Chicken, Sweet Potato, and Swiss Chard Soup

재료

1 tablespoon olive oil

8-ounce package fresh button mushrooms, quartered (3 cups)

1/2 cup chopped onion

1/2 cup chopped celery

1/2 cup sliced parsnips

8 cups unsalted chicken broth

2 8-ounce skinless, boneless chicken breast halves

3/4 teaspoon salt

1/4 teaspoon black pepper

10 oz bag of frozen sweet potatoes

3 cups spinach

1 teaspoon chopped fresh thyme

1/4 teaspoon chopped fresh rosemary

1 bag frozen corn

1 bag frozen carrots