Finding leftover mashed potatoes in the refrigerator the morning after Thanksgiving is like finding a half-finished bottle of leftover wine. It almost never happens. However, if you're lucky enough to have just a cup of creamy mashed potatoes, you can make a brand new quiche that has not a hint of leftover about it. (If you also have some leftover cooked broccoli, use it here. Nobody will know.) This quiche takes all of the ingredients of a steaming bowl of potato broccoli soup and reimagines them wrapped with eggs and dressed in a crust. What's not to love? You can make this at night, and reheat it for breakfast, brunch or a light supper. Leftovers never looked (and tasted) so good.