Cut the cold butter into small pieces.
Mix the flour with salt (and sugar, if using), then add the cold butter. Next, add a couple of ice cubes to the bowl of flour and butter. This will help keep the butter cold while you mix it in with your fingers.
Rub the butter and flour together between your fingers or palms.
Keep rubbing between your fingers and/or between your palms, until the mixture is sandy, with some pea-sized and larger chunks of butter. These chunks are important for a flaky crust.
Add one or two tablespoons ice water. Gently mix until the dough just begins to hold together. If needed, add another tablespoon of ice water. Do not add too much. You may not need all the water called for in the ingredients list. You want the dough to be moist but not wet. You should still have some small chunks of butter in the dough.
Use the heel of your hand to gently press and smear the butter into the flour. You are not kneading, just pressing and dragging the dough once or twice. This is a French technique called “fraisage”. Instead of fully mixing the butter in, you create thin streaks of butter throughout the dough. This keeps the gluten from developing too much and gives the baked crust that flaky texture we are after.
Stop working the pie crust dough when you still see some streaks and small pea -sized pieces of butter in the dough. Remove leftover ice cubes (they just pop out).
Form the dough: Gently gather the dough together and press into a flat disk about 2cm (3/4 inch) thick. Wrap tightly in plastic wrap or parchment paper and chill in the refrigerator for at least 1 hour (or up to 2 days). Chilling allows the gluten to relax and keeps the butter cold, which helps the crust bake up flaky and prevents shrinkage.
Roll out the dough: Either lightly flour your clean work surface and rolling pin and roll the dough from the center outward, rotating occasionally to keep the thickness even. Or do what I learned at the Cordon Bleu – roll out your dough in between two sheets of parchment paper. So much easier!
Fit the rolled out pâte brisée dough to your pie dish. If you used parchment paper, you can do this by just flipping the rolled out dough and parchment paper onto the pie dish. Otherwise, you can roll the dough onto the rolling pin and then unroll it onto the pie dish.
Use your rolling pin or a knife to cut off extra dough from the side of the pie dish if you like. (But you can also just bunch it up for a more rustic look)
Poke holes in the bottom with a fork to help even baking.