I constantly run across statements that it's not possible to make a flaky oil-based crust. However, this is simply not true.
My grandma's oil/milk based pie crusts are consistently flakier than any butter/shortening/lard based crust I've ever made or tasted.
However, it's important to point out that this bit of wisdom is so common because you cannot simply substitute oil for butter/shortening/lard in a traditional pie crust recipe.
A flaky oil based crust requires a different recipe and careful handling of the dough when mixing and rolling. For those interested, give this a try:
2 C flour + a little salt
5/8 C oil
5/16 C milk
It's easiest to use a glass measuring cup so you can measure
out the oil and then *pour the milk into the oil* before
pouring it into the flour.
Pour the liquid into the flour and *gently* stir the liquid
and flour together with a fork. You only want ~12-14 stirs.
*DO NOT* beat the mixture or knead the dough.
After this gentle mixing, pack the dough together and divide in half.
The dough should have a *wet/oily* consistency; it should *not* be dry and crumbly.
Roll the dough out between two sheets of wax paper.
If you mixed things correctly, the dough should have a
marbled or mottled appearance and should be wet enough
to patch together easily.
Makes enough for two pie shells (or a top and bottom crust)
If you haven't worked with crusts between wax paper before, here's the trick for transferring it to the pie tin:
Gently remove the top sheet of wax paper and place it lightly back on the crust.
Quickly flip the dough over (grab two corners and flip the crust).
Remove the sheet of wax paper now on the top.
Place your hand under the bottom sheet of wax paper and flip the crust into a pie tin.
Gently form the dough into the tin and then carefully remove the wax paper.
Cut any excess dough off the edges of the pie tin and use this to patch
any tears or fill in any gaps.
You can further improve the consistency (i.e., flakiness) of the top crust (or bottom crust if you're cooking the pie shell on its own for a pudding or fresh fruit pie) by rubbing a little milk on the surface of the crust and sprinkling a little sugar (or cinnamon/sugar for things like the top crust of an apple pie).
I've been using this recipe for 20+ years and friends/guests are always surprised that such a flaky/delicate crust was oil based. Others are surprised at how simple and easy it is to make. It's a great all purpose crust that I use with fruit pies, meat pies, pudding/custard pies, etc. The pie crust itself is great on its own (sprinkle some cinnamon and sugar on it after rubbing it with milk and then cook some "pie crust cookies").
I'm obviously biased because this is the crust that my mom and grandmother always made when I was growing up, but I find the consistency and flavor to be better than typical shortening crusts. (Although, to be fair, my mother-in-law makes an amazing lard/vodka crust and, frankly, some recipes call for a more shortbread-like crust).