Preheat oven to 425°F. In a large bowl, combine the apples, lemon juice, flour, sugar, and cinnamon; set aside.

Roll out two pie crusts. Place the bottom crust on a 9-inch pie plate, gently pressing the dough into the bottom of the pan. Pour the apple mixture into the bottom crust and dot with the butter. Cover the apples with the top crust, crimping the top and bottom crusts together all around and trimming off the excess dough. With a small knife, cut vents in the top crust to allow steam to escape while the pie bakes.

Brush the top crust and the crimped edge with the egg yolk mixture. This will help the top crust brown nicely. Bake for about 45 minutes, until the top is golden brown all over. Let the pie cool on a wire rack for at least 30 minutes before slicing.