Whisk together flour and sugar in a bowl.

Cut in cold butter using a pastry blender or two knives until the mixture resembles fine crumbs with some pea-sized pieces.

In a separate small bowl, mix egg yolk and cold water.

Drizzle the egg yolk mixture over the flour mixture.

Toss the ingredients together with a fork until the dough starts to clump.

Form the dough into a ball and flatten it into a disc.

Roll out the dough on a lightly floured surface.

Place the rolled-out dough into a pie or tart tin.

Chill the dough in the refrigerator for 30 minutes.

Preheat oven to 400°F (200°C).

For blind baking, bake the pastry for 15-20 minutes, or until the edges start to turn golden brown.

Alternatively, fill the pastry with your desired filling and bake as directed by the pie recipe.

If using a food processor, combine flour and sugar in the processor bowl and pulse to mix.

Add cubed butter and pulse until the mixture forms fine crumbs.

Drizzle the egg yolk and water mixture through the feed tube while the processor is running.

Once the dough starts to form, remove it from the processor bowl and proceed as instructed.