Choosing the wrong baking dish

Because quiche is essentially a savory pie, you should bake it in a pie pan, right? That would be yet another major blunder. Here's why you should never bake quiche in a pie pan. The short answer is that standard pie pans are insufficiently deep for quiche. A two-inch deep springform pan is your best bet. Not only will you achieve the desired height, but your quiche will bake more evenly and you will be able to easily remove and slice it. Instead of a pie dish, use a two-inch high metal pastry ring if you don't have a springform pan.

This is not to say that you can't use a pie pan; in fact, you'll see quiches baked in pie pans all over the Internet. However, most quiche recipes yield too much filling, resulting in an overflowing dish of custard. When possible, use a different vessel and only use pie pans if you don't have any other options.