Measure out all the ingredients (working fast is really important so the butter does not melt).

Whisk flour, salt, and sugar together in a large bowl.

Cube cold butter and add to the dry ingredients.

Rub the flour into the butter with fingertips until the mixture resembles corn meal/small pebbles.

Add the lightly beaten egg. Use a wooden spoon to mix the egg in.

Continue mixing the dough with the spoon as you add water in (1 tablespoon at at time).

Once the dough begins to form into a ball, you can mix the dough by hand. You do not need to add in all the water, and do not want the dough to become too sticky. (if the dough is too sticky, add in 1 tablespoon of flour as needed until you get a workable dough)

Cover the dough in plastic wrap and refrigerate for 1 hour or until the dough is firm.

Place the chilled dough on a lightly floured surface and roll it out to desired size and thickness.

Shape the dough and bake it based on instructions from the pie and filling recipe.