Place the butter pieces into a small bowl and put in the freezer for 10-15 minutes while you work on the rest of the crust.

In the bowl of your food processor, add the flour, sugar, and salt and pulse a few times until incorporated. Mix together the sour cream and 1/3 cup of the ice water in a small bowl. 

Gently scatter the cold butter pieces over the flour mixture in the food processor, making sure there are no large clumps of butter pieces. Pulse until the butter pieces are about the size of peas, up to ten pulses. 

Add half of the sour cream mixture and pulse until incorporated, 2-3 pulses. Add the rest of the mixture and pulse 2-3 more times. To test if the dough is ready, pinch a small amount between your fingers. It should clump together if it is ready. If it is too dry to stick together, add more ice water in tablespoon increments until it is ready. Pulse until the dough is starting to form larger clumps.

Dump the crust mixture onto a well-floured work surface. Divide the mixture in half and work each half into a ball. Wrap each half tightly with plastic wrap and place in the fridge to chill for at least 30 minutes to an hour. 

Combine all filling ingredients into a large bowl and stir well to coat. Set aside.

Adjust the oven rack to the lowest position and preheat oven to 500 F.  

Remove the dough from the fridge. On a well-floured work surface, roll one of the halves out to about 12 inches. Place inside the pie plate, making sure it is pressed into the edges and there is enough to hang over the sides. Roll out the other half of the pastry to 12 inches as well.

Place the apple mixture inside the shell and press lightly to make sure the apples are in there nice and tight. You can arrange the apples if needs be. Just make sure there are no large air pockets. 

Place the other half of the pastry over the top and crimp the edges. Cut a vent hole in the middle. Lightly brush the top with the egg white and sprinkle evenly with the raw sugar. Cut a vent hole in the middle.

Place the pie plate on a rimmed baking sheet and reduce the oven temperature to 425 F (This is important!). Bake until the crust is golden, around 25 minutes, then reduce the oven temp to 375 F.  Rotate the baking sheet and baking for another 25-35 minutes until the crust is a deep golden brown and the filling is bubbling. (Watch the edges of the crust for any darkening areas. If the edge of the crust is browning quickly, cover the edges with aluminum foil.)

Remove from the oven and let cool for several hours before eating.