In a large bowl, combine the flour and salt. Cut in the cold butter until the mixture looks like coarse crumbs.
Stir in cold water a little at a time until the mixture can formed into a ball.
Shape the dough into a disc and cover with plastic wrap. Place in the refrigerator for about 1 hour until firm.
In a large bowl, combine the cherries and the ½ cup of sugar and let sit for about 15 minutes. Drain the juice and reserve 1/4 cup.
In a sauce pan over medium heat, combine reserved cherry juice, cherries, lemon juice, and cornstarch. Cook for about 5 minutes or until the cherries soften and the liquid has thickened. Remove from heat and let it cool completely.
Once the dough is ready, roll it out onto a floured surface to approximately 1/4-inch thick. Cut about 6 to 8 4 1/2 to 5-inch circles, re-rolling the scraps.
Place a dough circle on a flat working surface and brush the top with egg white before filling.
Scoop about 1 tablespoon of the cherry mixture onto the dough and fold over and seal the edges by crimping with a fork. With a knife, cut 3 small vent holes on the top.
Repeat with remaining dough and filling mixture. Arrange the assembled pies in a single layer on a parchment-lined baking sheet, cover it with plastic wrap, and freeze for at least 30 minutes.
Remove the plastic wrap and brush the tops of the pies with egg white and sprinkle with turbinado or granulated sugar.
Bake on the middle rack of a preheated 350 F oven for 30 minutes or until the tops are golden brown.