Winter Harvest Vegetable Soup Recipe

3 medium carrots, halved and thinly sliced 3/4 cup chopped celery 1 medium onion, chopped 2 green onions, thinly sliced 1 tablespoon butter 1 tablespoon olive oil 1 garlic clove, minced 7 cups reduced-sodium chicken broth or vegetable broth 3 cups cubed peeled potatoes 2 cups cubed peeled butternut squash 2 large tart apples, peeled and chopped 2 medium turnips, peeled and chopped 2 parsnips, peeled and sliced 1 bay leaf 1/2 teaspoon dried basil 1/4 teaspoon dried thyme 1/4 teaspoon pepper Additional thinly sliced green onions, optional