Note: This recipe makes enough for a 9" double pie crust. If you just need a bottom crust, I recommend making ¾ of the recipe so you have enough to work with. Or you can make the full recipe and freeze any leftovers for another time.
Make the buttermilk: To make the vegan buttermilk, add the non-dairy milk and apple cider vinegar to a bowl and place in the freezer for 10-15 minutes until icy cold.
Preparation: Lightly grease a 9-inch pie tin with oil or vegan butter, dust it with flour, and then knock off any excess flour so it is lightly coated. You can also add a round of parchment to the base.
Method 1 (when using a food processor): Add the flour and sea salt to the food processor and blitz for a minute until evenly mixed. Add in the cold cubed vegan butter and pulse the mixture until roughly combined, about 20 seconds or less (see images in the blog post above for reference).
Slowly pour the ice-cold vegan buttermilk into the food processor while blitzing to incorporate it into the dough - this should take no longer than 5-10 seconds, do not overmix.
Turn out the pastry onto a lightly floured surface and gently shape it into a large disc. Wrap it in plastic wrap and place it in the fridge to chill for at least an hour.
Method 2 (when making by hand): Add the flour and salt to a large bowl and mix well. Add in the cold butter cubes and rub the butter into the pastry with your fingertips using the rubbing-in method. You should be left with almost a crumb consistency, but do not overwork the dough, a few lumps of butter in the mixture are fine.
Add the ice-cold vegan buttermilk in 2 parts to the bowl and carefully bring the dough together using your hands. If the dough is very wet, you can add a few more tablespoons of flour to bring it together but do not mix it for more than a few seconds.Turn out the pastry onto a lightly floured surface and gently shape it into 2 separate discs. Wrap the pastry discs in plastic wrap and place them in the fridge to chill for at least an hour.
Meanwhile, preheat your oven to fan 190°C/374°F or conventional 210°C/410°F. Also, preheat an aluminum tray or baking sheet in the oven.
Remove the dough disc from the fridge and let it sit at room temperature for 5 minutes before rolling out. If using a top and bottom crust, divide the disc into 2 portions - making the bottom crust slightly more as it will take up more surface area.
On a lightly floured surface, roll out the dough to around ⅛ inch in thickness, then fold it over and roll again. Repeat this process so that you have folded the dough around 4 times, dusting with flour as needed. Finally, roll the dough to a ⅛ inch in thickness with a circumference larger than your pie tin.
Carefully lift the pastry into the tart tin using your rolling pin. Gently press the dough into the base and sides of the tin, being careful not to stretch it. Use scissors to trim off the excess pastry around the edges of the pan.
To crimp the edges of the dough using the pinch method as shown in this video or simply press the edges down using a fork. Pierce several holes into the base of the pastry using a fork.
Top crust (for fillings that are baked): If using a top pie crust, roll out the second pastry disc, add the pie filling to the pie (eg: apple pie or cherry pie), and top with the second round of pastry. Trim and crimp the edges of the top layer of the crust. Melt the 2 tablespoons of vegan butter and brush it on top of the pastry in an even layer. Sprinkle with granulated sugar. Bake according to the pie recipe instructions.
Blind-Baking (for fillings that are not baked): Take a sheet of parchment paper and cut it into a circle slightly larger than the pie tin. Scrunch up the parchment, and place it on top of the dough. Fill the base with pie weights (you can also use dried beans, rice, or lentils). Place the pie into the oven on the preheated baking tray and par-bake it for 20 minutes.Carefully remove the baking beads and parchment and continue to bake the crust for another 15-20 minutes until golden brown. Cool completely to room temperature, but do not remove the crust from the tin until completely cool.
Storage: You can freeze the uncooked pastry in an airtight container for up to 3 months. Thaw it in the fridge overnight before using it. It can also be stored in the fridge wrapped in plastic wrap for 3 days prior to baking.
Make sure that you work with cold fats. The vegan butter and vegan buttermilk both need to be cold for the best results and to get a crisp flaky pastry shell.