Make the Pastry Dough:

1. In a food processor, add flour, sugar, salt and cubed butter. Pulse mix on and off for about 1 minute, until the flour mixture turns into a small breadcrumb-like consistency.
2. Drizzle ice water into the mixture (ice water is the key here). Close the lid and continue to pulse mix on and off for another 1 minute. If you squeeze the crumbs together and they stick together, that means the crumbs are good to go.
3. Transfer the dough (crumb-like) into a large ziploc bag and squeeze with your hands to bring all the loose crumbs together until it turns into a nice and smooth dough ball.
4. Divide the dough ball in half and flatten to form 2 equal discs. Wrap the discs separately in plastic wrap and refrigerate for at least 1 hour.

Make the Filling:

1. In a large mixing bowl, combine pitted and halved cherries, cornstarch, sugar, cinnamon, lemon juice, and lemon zest, and mix together. Set aside for assembling.

Assemble the Pie:

1. Preheat the oven to 400 F.
2. Unwrap each dough disc and place in between 2 pieces of parchment paper or plastic wrap. Roll each dough disc into a 12-inch circle using a rolling pin.
3. Transfer the first dough disc onto a 9-inch pie pan and gently press down to form into the bottom pie crust.
4. Slowly pour the cherry filling mixture into the dough-lined pie pan (make sure to not transfer any liquid from the bowl). Use a spatula to spread the filling evenly across. Discard any remaining liquid in the bowl. Add cold cubed butter on top of the cherry filling.
5. Carefully place the second dough disc on top of the filling (this will form the top pie crust). Make sure it covers the pie pan entirely. Gently press the edges of the top crust and the edges of bottom crust together. Pinch them together with your fingers, along the entire edge of the pie, and crimp to seal.
6. Use a knife to make 4 slits on top of the top pie crust for ventilation. Gently brush egg wash over the top crust and edges.
7. If your oven has not preheated at this point, store the assembled pie in the fridge to prevent the pie crust from disintegrating (the butter in the dough melts quickly at room temperature).

Bake the Pie:

1. Transfer the cherry pie pan into the oven and bake in a preheated 400 F oven for 20 minutes, until the edges of the pie start turning golden brown. Reduce the oven temperature to 350F and bake for additional 40 minutes until the pie crust is golden brown. You might see the pie filling ooze out a little.
2. Allow the pie to cool in the pan at room temperature for 1 hour before serving.
3. Slice and serve with a scoop of vanilla ice cream.