Yellow Squash Casserole

Name: Yellow Squash Casserole
Ingredients: 4 lb yellow squash (10 medium), trimmed, halved lengthwise, and sliced crosswise 1/8 inch thick; 1/4 cup vegetable oil; 2 teaspoons salt; 2 teaspoons black pepper; 2 medium onions, chopped (2 cups); 1 green bell pepper, chopped; 1 red bell pepper, chopped; 7 tablespoons unsalted butter; 4 slices firm white sandwich bread with crust, coarsely ground in a food processor (about 2 1/4 cups); 1/4 cup all-purpose flour; 1 3/4 cups reduced-sodium chicken broth (14 fl oz); 1 cup sour cream