Vegetarian Gumbo

Name: Vegetarian Gumbo
Ingredients: ½ cup all-purpose flour; ⅓ cup extra-virgin olive oil; 1 small butternut squash, peeled, seeded and cubed (3/4- to 1-inch); 2 cups chopped yellow onions; 2 cups chopped poblano peppers; 1 cup chopped celery; 8 cups low-sodium vegetable broth; 1 (28 ounce) can whole plum tomatoes, drained and crushed; 1 ¾ teaspoons salt; 3 cups fresh okra, trimmed and sliced (3/4-inch); 3 cups chopped zucchini; 2 (15 ounce) cans no-salt-added pinto beans, rinsed; 2 tablespoons hot sauce; 1 tablespoon red-wine vinegar; ½ teaspoon ground pepper; 4 cups cooked brown rice, warmed