Not all 9-inch (23 cm) pie plates are the same. Of course some are metal and others are ovenproof glass, and then there are ceramic, but what I am talking about here is volume. There are deep-dish “9-inch” pie plates that are actually more like 9 ½ -inches (24 cm) across and deeper than the classic 9-inch (23 cm). They might both be labeled as 9-inch (23 cm) pie plates. You have to know what you are using because they are not the same, and are not interchangeable in recipes.   This dish demands a deep-dish pie plate that measures 9 ½-inches (24 cm) across and 1 ½-inches (4 cm) in depth, or you will have serious overflow! Even so, we suggest placing your pie plate on a half-sheet pan, just in case. In the image below the deep-dish plate is in the rear. You can see how much larger it is!