Frozen pies take longer to bake than freshly made pies, and they should be baked from the frozen state.
Freezing an unbaked pie yields a better fresh fruit flavor than freezing a baked pie, but the bottom crust tends to get soggy unless you follow the recommendation immediately below.
Freeze the filling and crust separately to prevent the fruit juice from penetrating and softening the lower crust during freezing.
Method:
Freeze the fruit filling in one plastic wrap lined pie pan and the bottom dough in another unlined identical size pie pan.
After freezing put the filling, without the plastic wrap, into the frozen bottom dough.
Let the outside edge of the bottom crust partially thaw. Brush that edge with a light coating of whisked egg white.
Cover the pie with room temperature dough, pinch the top dough together with the outside edge of the partially thawed bottom dough, cut slits as necessary, and freeze the combination.
Wrap the entire pie tightly in aluminum foil. Return the pie to the deep freeze until you are ready to bake it.
Baking:
Always put frozen pies on cookie sheets prior to baking to catch any juices that might overflow. Putting aluminum foil between the pie pan and the cookie sheet will usually keep the cookie sheet clean even with juice overflow, and that makes cleanup easier.
For baking, use 425 degrees for 25 minutes and then 350 degrees for 20 to 30 minutes, covering the top crust with aluminum foil if the crust bakes to a light golden color before the end of the second baking period.
Other Essential Considerations:
Light colored fruit pies (Peach, etc.) will retain color better if 1/2 tsp. of ascorbic acid is added to the filling prior to freezing.
Add an additional 1/2 tbsp. of cornstarch to juicy fillings prior to freezing to avoid later boiling over during baking. Tapioca is an even better choice as a supplemental thickening agent, or use modified food starch like Thermoflo® if it is sold at your supermarket.