My All Time Favorite Gumbo

Name: My All Time Favorite Gumbo
Ingredients: 1 cup vegetable or canola oil; 1 1/3 cups all-purpose flour; 3 large bell peppers, cored and diced (I used one red, one yellow, one green); 2 large celery stalks, diced; 1 small white onion, peeled and diced; 2 cups fresh or frozen chopped okra; 1 pound (16 ounces) andouille sausage, sliced; 5 cloves garlic, minced; 1 (14 ounce) can fire-roasted tomatoes; 1 tablespoon Creole seasoning; 2 teaspoons dried thyme; 1-2 teaspoons cayenne, to taste; 1-2 teaspoons salt, to taste; 1-2 teaspoons freshly-cracked black pepper, to taste; 6 cups chicken stock; 2 cups shredded cooked chicken; 3 bay leaves