Flans contain a lot of fat, so they freeze at a lower temperature than most foods. Recipes typically advise against freezing flans because they have a reputation for not freezing well, but that isn't true. Basic dessert flans contains whole eggs, cream and sugar -- the same ingredients in ice cream, except for the egg whites. Ice cream freezes at 10 degrees Fahrenheit, and you can't pierce it with a knife at 0 F. To freeze a flan, savory or sweet, you just have to wrap it well and place it in a cold freezer with good air circulation.
Adjust your freezer to 0 degrees Fahrenheit if it's not at that temperature already. Allow at least 2 hours for the temperature to drop if you don't have a thermometer in the freezer.
Let the flan cool to room temperature and slice it into quarters. Small pieces of flan freeze faster and better than an uncut flan.
Wrap the flan pieces in laminated freezer paper, then wrap them with several layers of plastic film in alternating perpendicular directions.
Slide the flan or partial flan in a heavy-duty freezer bag and mark the date on it. Make space in the freezer so air circulates on all sides of the flan.
Store sweet flans and tarts in the freezer up to 1 month for best results. Freeze savory flans such as quiches and meat for 4 to 6 months.
Let the flan thaw in the refrigerator for a few hours, then let it reach room temperature before unwrapping it. Heat savory flans to 165 F before serving.