You can eat every part of a proper pie. You can't eat a ceramic dish.A casserole is a large, deep pan used both in the oven and as a serving vessel. The word is also used for the food cooked and served in such a vessel, with the cookware itself called a casserole dish or casserole pan. "Casserole" should not be confused with the word "cacerola" which is Spanish for "cooking pot". Wikipedia
Mine, sir, was a pie