Add the flour, vegan butter, sugar, salt, 1 tablespoon of non-dairy milk, and vanilla to a food processor. Blitz for a few seconds until the ingredients are mixed and form a loose dough. Note here, you can add more of the non-dairy milk to get the dough to come together a little. Then remove from the food processor and press the dough into a ball and flatten it into a disc.
Wrap in clingfilm or place in an airtight container and refrigerate for 30 minutes.
Note, you can store this uncooked pastry dough in the refrigerator for up to 2 days. Wrap the pastry disc tightly with clingfilm, or roll it into the tart tin and wrap it in plastic wrap so it's ready to bake when you need it. You can also freeze it for up to 2 months. Simply defrost it in the fridge overnight before use.
While your crust is cooling, preheat the oven to 325°F or use the convection setting at 350°F. Lightly grease the base and sides of a round 9.5" tart tin or pie pan with oil or vegan butter and lightly dust with flour; if desired, you can also line the base with parchment paper.
Roll out the chilled dough so that it is an inch or so larger than the circumference of the tart tin, approximately 10.5”. Then gently fold the dough into fourths, and gently lift the pastry over the tin or pie pan, placing the center of the triangle in the center of the tart tin or pie pan, and gently unfold the dough over the tin or pie pan. Then use your fingers to gently ease the pastry into the side of the tin, making sure the dough is pressed into the edges of the tin or pie pan.
Note, if your pastry breaks or cracks, do not worry, just press the dough together to seal any cracks or breaks; the filling will cover any imperfections.
Use a knife or pastry scissors to cut around the top edges of the tin, allowing the dough to rise slightly higher than the sides of the pan. Pierce the bottom of the dough several times using a fork.
Take a sheet of parchment paper and gently place it on top of the pastry, and fill the base of the crust with dried beans, rice, lentils, or baking beads.
Parbake the crust in the oven for 15 minutes. Remove from the oven and carefully remove the beans/baking beads from the tart.
If using a baked filling such as apple tart or apricot tart, follow the directions in that specific recipe for the remaining bake time; otherwise, move on to the next step to fully blind-bake the tart shell.
After the beans have been removed, cook the crust for another 10 to 15 minutes to fully bake the crust. It should have a nice golden brown color.
Place the tin or pie pan on a cooling rack and cool it to room temperature before adding any fillings such as pastry cream, lemon curd, or coconut cream*.
Allow the tart to cool completely before removing it from the tin.