Is there a secret to keeping my pumpkin pie filling from separating from the crust?
A custard pie filling separates from the crust because of shrinkage, which is a normal part of the cooling process. The fact is, all baked goods shrink as they cool due to the evaporation of moisture during baking; with a pie, the filling and crust are shrinking in opposite directions, which often results in separation. There are ways to reduce the chance of this happening, though. One is to avoid extreme changes in temperature; choose a spot to cool your pie that is free of drafts, and do not put the pie in the refrigerator until it has cooled completely.
I prefer serving a pie the day it is made so that it doesn’t need to go into the fridge. Also, I always prebake the pastry crust for pumpkin and other custard pies to give the crust a chance to shrink before the filling is added. Even though the filling will still shrink upon cooling, separation will be minimized.
If you must bake a pumpkin pie a day ahead, your best bet may be to disguise any separation. I like to sprinkle chopped toasted pecans or almonds around the edge of the filling before serving. I’ve also used crushed gingersnaps or biscotti. If you like, you could pipe whipped cream decoratively around the edge. Realize that the separation may be unavoidable, and that one bite of a homemade pumpkin pie will take everyone’s mind off how it looks.