In a food processor, combine flour, salt, sugar, and butter cut into cubes.Press the dough button to pulse until this mixture is combined and butter is in small pea-sized pieces. Slowly add ice water a tablespoon or so at a time until dough becomes well combined and cohesive. Cut the dough into to pieces formed into a disc. Try not to handle the dough too much, you don't want the butter to melt!Chill dough for 2 hours. This will help the butter stay cold and create pockets of flakiness as it bakes. Roll out dough on a lightly floured counter. Use a 3" cutter to cut 8 circles. Brush egg white around the edge of 8 circles, and add a spoonful of fruit filling to the center. Top with additional 8 pie circles or create a lattice topping to cover the pie filling. Press edges and seal with a fork. If you fully cover with another pie circle, be sure to cut a vent on top.Brush pies with remaining egg white and top apple pies with course sugar if desired. Bake at 375° for 20-25 minutes or until golden.