Late Summer Minestrone with Butternut Squash and Fresh Corn

1. Heat oil in 5-qt. Dutch oven or other large soup pot over medium heat. Add leeks, celery, bell pepper, and salt, if using. Cover, and cook 6 to 8 minutes, or until veggies are softened, stirring occasionally. Uncover, and continue cooking 5 to 6 minutes more, or until celery is somewhat shrunken and leeks are browned. 2. Add garlic, sage, Italian seasoning, and bay leaf. Stir 30 seconds, or until fragrant. Add tomatoes and 8 cups water, and bring to a boil. Season with salt and pepper, if desired. Reduce heat to medium-low, and simmer 20 minutes. Add squash, cover, and simmer 10 minutes. Add green beans, white beans, and corn; simmer 10 minutes more, stirring occasionally. Just before serving, stir in vinegar.