In a food processor, measure out the flour, sugar, salt. Cube the butter and add it to the dry ingredients. Pulse the butter until it is pea-sized.
Add the dry ingredients/butter mixture to a stand mixer and add the sourdough starter. Keep the stand mixer on a low setting.
Take a tablespoon of water and gradually add the water until the dough starts to form.
Once the dough has formed, knead the dough with your hands for about 3 - 5 minutes. This will make the pie crust super flaky.
Cut the pie crust in half and wrap them in plastic wrap. Chill the dough in the fridge for at least 20 minutes.
Preheat your oven to 400 degrees.
While the pie dough is chilling, slice the pears, grate the ginger, and add them to a bowl with the melted butter, cinnamon, and vanilla extract. Mix everything well.
Roll out the pie crust into a pie dish. Poke holes in the bottom of the crust with a fork, and brush with egg wash. This will prevent bubbles from forming and a soggy bottom.
Add the pear and ginger filling to the middle of the dish, and fold the edges of the pie crust around the pear and ginger filling.
Brush the rest of the pie crust with the egg wash.
Bake at 400 degrees for 25 minutes. Let your pie cool for about 5-10 minutes before eating and enjoy!