Custard pies, with their foundation of eggs, milk, sugar, and flavorings, can be delicate and sleek. Because they depend solely on eggs for thickening, you need to keep an eye on them in the oven and watch the baking time, remembering that the center of the pie will continue to firm up as the pie cools. A custard that is overbaked can be a little grainy and watery, yet is still eminently edible. Just bake your next pie a little less.
Unfortunately, custard pies often get a bad rap for having a soggy bottom crust. There are all sorts of suggested remedies for preventing this, from prebaking the pie shell until it is partially crisp before adding the filling, to warming the filling on the stovetop before pouring it into the pie shell, sprinkling the pie shell with sugar, or brushing the pie shell with egg white or melted jelly. For the home cook, all these ideas simply add another step to an already daunting process. Because my goal is to get you to bake pies, not scare you away from them, I’ll let you in on my simple technique for minimizing the soggy crust syndrome: Bake pies in a glass pie plate, in a fully preheated oven, and serve them within a few hours. It isn’t a perfect solution, but it’s a manageable one.
Once the filling has set and reached room temperature, try to serve custard pies as soon as possible. These are, as one pie-baking friend used to say, real “right now pies.” But if you have leftovers, remember that any pie with a milk- or egg-based filling should be refrigerated for storage.