Canned tuna is a wonderful addition to quiche, adding protein and flavor without any extra fuss. Mushrooms and spinach are also incorporated into the filling which is baked in a tender and flaky crust made from homemade pie dough. Of course you can always substitute a store-bought dough instead of making your own, but once you've mastered the simple recipe, it will become your default for quiche and other pies and tarts.