You can store any leftover quiche wrapped well in the fridge. You can also heat it in the microwave, and yet the crust tends to get soggy. For the remaining few slices, this is ok. If I have a large piece of quiche left over, I prefer to heat it in the microwave for a minute, then place it in a hot oven, for 8 to 10 minutes, until the crust gets crisp again. Frozen quiche can be baked in the oven from frozen for about 45 minutes to an hour at 170 F or 350 F.