Basic Green Bean Casserole. 1 can (10.5 ounces) Cream of Mushroom Soup (or Cream of Celery Soup) 1/2 cup milk 1 teaspoon soy sauce 4 cups cooked cut green beans (3 14.5 oz. cans French cut green beans) 1 1/3 cups French Fried Onions ("divided") Heat in oven for 350°F 25 minutes or until hot and bubbling.