Place the quiche on the baking sheet, and put it in the freezer. Once the quiche begins to harden, remove it from the baking sheet, wrap it in freezer paper and seal it inside a freezer bag. Then, return the partially frozen quiche to the freezer for full freezing and storage.
A frozen, baked quiche does not need to be thawed out in advance of reheating. Remove the freezer bag and paper, and reheat it for about 25 minutes in an oven that has been preheated to 350 degrees Fahrenheit.Learn more about Freezing Food