Chicken Soup With Wild Rice and Mushrooms

2 tablespoons butter 2 cups onions , peeled and diced 2 cups carrots , diced 2 cups celery , diced 2 cloves garlic , peeled and diced 1 cup wild rice 8 cups[...]

2 tablespoons olive oil 2 boneless skinless chicken breasts , cut into thin strips 2 cups thinly sliced portabella mushrooms (stems removed) 1 medium onion ,[...]