Cut your butter into small cubes about ½" x 1"2 and place into the freezer. Measure out your water and place it in the freezer as well. Chill for at least 15 minutes.
Add the flour, arrowroot powder, salt and sugar to a large bowl. Mix together until well combined. If it is especially warm in your home, you can freeze the flour to cool it down.
Add the frozen butter to your dough. Make sure each cube of butter is coated with flour on all sides. Then working quickly, squish the butter from cube shaped into flattened discs about the size of quarters. If your mixture starts to feel wet or greasy at any time, place the whole bowl back into the freezer to chill it. It's important to keep the butter very cold throughout the process.
For extra flaky crust, you can leave large chunks of butter but for lattice work, small bits of butter work better. I try to work my butter into the flour until it is about pea sized.
Next make a well in the flour/butter mixture and pour in half of your chilled water. Toss the flour and water together to combine. Add half of the remaining amount of water and continue to toss together. If you get any big chunks break them apart because they will be very wet inside. You want the moisture to be evenly distributed. Continue adding water in this way until your dough reaches a shaggy state which is just sticking together.
Combine all of your dough into a ball. Divide into two parts. Shape each into a patty and wrap separately with plastic wrap. Refrigerate a minimum of 2 hours up to overnight.
Remove one piece of chilled dough from your refrigerator. Place a piece of parchment paper on your counter and dust with about 1 tablespoon of flour.
Put your dough on the floured surface and sprinkle another ½ tablespoon flour on top of the dough. Begin rolling out the dough. If your dough sticks to the rolling pin at any time, sprinkle with a bit more flour. Roll the dough until it is large enough to fit your pie pan. Repeat with second dough ball.
Place rolled out dough sheets on a baking sheet and put it back into the refrigerator for 1 hour. While it's chilling, prepare the pie filling.
For the pie filling
In a large bowl combine the apples, cranberries, lemon juice, sugar, arrowroot powder, cinnamon, ginger, salt and vanilla. Stir until the fruit is well coated with the sugar and spices.
To assemble the pie
Preheat the oven to 400 degrees F.
Remove one chilled sheet of pie dough from the refrigerator.
Flip the first sheet of the dough into your pie pan and gently work it into the shape of the pan. Take care not to press the dough in as it will stick to the pan after baking. If you're planning a decorative crust for the edge, leave an overhang of about ½", otherwise trim the dough to the edge of the pie plate. Use the leftover scraps of dough to patch any holes or tears that may have occurred.
Pour the pie filling into the pie pan.
Take your second rolled sheet and cut it into strips for lattice. Place the strips across the top of the pie and then add the alternating strips. See the text above for more detailed lattice instructions.
Crack your egg into a small bowl and beat until smooth. Add about 1 tablespoon water. Using a pastry brush, stick the edges of your lattice to the bottom crust with a little of the egg wash. Once all of the edges are stuck down, trim the lattice to the edge of the pie pan. Crimp the crust into your favorite design. NOTE: For vegan pie use a little water instead of egg wash to stick the lattice work down.
Brush the top of the pie crust all over with the remaining egg wash (OMIT for vegan pie). Sprinkle with sanding sugar (optional)
Place in the freezer for 15 minutes prior to baking. This will keep any crust designs from melting and losing shape.
Place the prepared pie on a baking sheet and bake on the lowest rack of your oven. Bake for 60 minutes. If the top crust begins to brown too much, you can cover loosely with aluminum foil.
Remove baked pie from oven and cool about 2 hours before slicing.
Notes
For King Arthurs Measure for Measure flour use 2 ⅓ C for your pie crust. Additional flour measurements can be found in my downloadable pie guide.