Chop the butter into small cubes. Add the cubes to a bowl and place them in the fridge or freezer for 10 minutes to ensure it's cold.
Add the flour, sugar, and salt to a large mixing bowl and mix them together with a fork or spatula. Add the cold butter cubes to the flour.
Use a pastry cutter to cut the butter into small pieces into the flour, or use your fingertips to rub the butter into the flour. The end result should be like coarse bread crumbs with a few pea-sized butter pieces in the mix. If the butter is melting at any point, place the bowl in the refrigerator.
Add the lemon juice or vinegar to the ice-cold water. Drizzle around 3/4 of it all over the flour.
Use a spatula or your hands to combine the dough. Add any extra water slowly, 1/2 a tablespoon at a time. The dough should hold together easily when pressed but not be sticky. If it is crumbly, add a bit more water.
Tip the dough onto a lightly floured bench and form it into a mound. Wrap the dough up tightly and place it in the fridge for 30 minutes before continuing with the next step.
Push the dough Into a mound on a lightly floured work surface. Use a rolling pin to roll the dough into a rough 10-inch/25cm rectangle. There's no need to measure it perfectly; just lengthen it to around this size.
Fold the bottom β
of the dough up to the middle, then fold the top β
of the dough over top to make a pamphlet shape.
Turn the dough aquarter turn and repeat this process once more.
Once finished rolling, cut the dough into two and use your cupped hands to gently shape each piece into a flat disc.
Wrap the dough discs up tightly. Chill it in the fridge for at least an hour or up to 2 days before using.
See instructions on how to blind-bake or fully bake a pie crust in the above post.