Besides homework, nothing signifies the return of fall quite like a gooey grilled cheese sandwich served with a side of creamy tomato soup. The only way we could possibly improve this time-honored after-school pairing is to combine the soup and sandwich into a hearty casserole that's built just like lasagna. Every bite of this dish has the perfect balance of tomato soup, melted cheese and buttery bread. Sound complicated? It's not. Read on to see how easily it's done, step by step.