This vegetarian quiche reheats well either in it's entirety or as leftovers. Leftover quiche slices can be heated individually in the microwave for quick weekday breakfasts The crust won't be quite as crisp, but the flavor is all still there. To reheat a full quiche that you've already fully baked, let it warm in a pre-heated 350° (175° C) oven until the center is warm. You can check by inserting an instant read thermometer into the center and it will read 165° F (73° C). For a cold quiche, this will take 30-35 minutes. It will heat much faster if the quiche is already room temperature. You may want to use pie shields or wrap foil around the edges of the pan to keep the crust from burning.