Which famous dish has minced beef topped with mashed potatoes and baked until crispy?

Shepherd's pie

Traditionally, what should people avoid crossing paths with on Halloween night? What was America's policy at the beginning of World War II? What famous American military leader later became the 18th President of the U.S.? Which country built and operated the supersonic Concorde aircraft along with the United Kingdom? Who is Kirby's notable penguin-like rival and occasional friend from the series?