Roasted Sweet Potato and Corn Soup

Name: Roasted Sweet Potato and Corn Soup
Ingredients: 1 lb sweet potato, peeled and cut into 1/2 inch pieces; 1 cup frozen corn, thawed; 1 celery rib, finely diced; 1/2 onion, finely diced; 1 garlic clove, minced; 1 teaspoon dried thyme; 6 cups chicken broth or 6 cups vegetable broth; 1 potato, peeled and cubed; 1/2 teaspoon dried parsley; salt and pepper; olive oil