Cut butter into flour using a food processor until the mixture resembles coarse crumbs.

In a separate bowl, combine egg, salt, water, and vinegar.

Pour the wet ingredients over the flour mixture in the food processor.

Pulse until the dough just comes together, forming a ball.

Chill the dough for 30 minutes.

Divide the dough into 4 equal portions.

Roll out each portion and place in pie pans.

Flute the edges of the crust.

Use as needed and freeze the remaining crusts.