Remove the pits from the cherries and put into a mixing bowl.
Add lemon juice, sugar, corn starch and cinnamon. Mix well until no white powder can be seen. Set aside in refrigerator.
Lay one pie crust at the bottom of the pie tray. Pour the cherries and juices into the pie crust. Distribute finely diced cold butter on top.
Cut second pie crust into 1-inch strips. Create a lattice on top of the pie. Fold the edges in with the first crust. Put pie into the refrigerator.
Pre-heat oven to 425 degrees F
Make egg wash with egg, milk and 1 tbsp sugar. When oven is ready, take pie out of the refrigerator and put it on a baking dish lined with aluminum foil. Apply egg wash generously over the top of the pie. Sprinkle sugar over the pir crust.
Bake pie in oven for 25 minutes at 425 degrees F
Reduce oven temperature setting to 350 degrees F and continue baking the pie for another 30 minutes.