- Combine the flour, sugar and salt in a large bowl. Add the oil. Using a pastry cutter, electric beaters or a mixer fitted with the paddle attachment, blend until the flour looks evenly crumbly in texture.
- Add the butter and cut in until the dough is rough and crumbly but small pieces of butter are still visible.
- Place the water and vinegar (or lemon juice) in a small bowl, stir together and then add all at once to the flour mixture, mixing just until the dough comes together. Shape it into two discs, wrap well and chill until firm, at least one hour.
- If you are not making a pie immediately, refrigerate the dough, well wrapped, for up to two days, or freeze it for up to three months. Thaw it overnight in the fridge before rolling.'
Use the full recipe if you’re making a double-crust pie, or just half if you want either a pie shell or a top, but not both. Working with cool—but not ice-cold—butter is easiest. Pull your butter from the fridge about 30 minutes before making your dough and it will cut into the flour quickly and more evenly.
Adding a little vegetable oil to the flour before adding the butter is another secret for tender and flaky pie dough. The oil coats the flour so that it won’t overhydrate when the water is added. Too much water develops the protein in the flour, which is why a crust becomes tough or shrinks when it bakes.